Method for fine pattern formation

ABSTRACT

There are provided an apparatus for fine pattern formation, which can form a fine pattern with high accuracy by direct writing with ink, a production process of fine nozzles provided in the apparatus for fine pattern formation, and a method for fine pattern formation. Fine pattern formation with high accuracy could have been realized by the apparatus for fine pattern formation, comprising: a silicon substrate; a plurality of fine holes which extend through the silicon substrate from the surface of the silicon substrate to the back surface of the silicon substrate and have a silicon oxide layer on the wall surface thereof; fine nozzles which are protruded, integrally with the silicon oxide layer, on the back surface side of the silicon substrate from each opening of the fine holes; a silicon nitride layer provided on the surface and side of the silicon substrate; a support member provided on the surface side of the silicon substrate; an ink passage for supplying ink to the opening of each fine hole on the surface side of the silicon substrate; and an ink supplying device connected to the ink passage.

FIELD OF THE INVENTION

[0001] The present invention relates to an apparatus for fine patternformation, a process for producing fine nozzles, and a method for finepattern formation, and particularly to an apparatus for fine patternformation, which can be applied, for example, to pattern formation forthe production of liquid crystal displays, plasma displays, and flatdisplays of electroluminescence or the like, and conductor patternformation and correction of conductor patterns of printed wiring boards,a process for producing fine nozzles used in the apparatus for finepattern formation, and a method for the fine pattern formation.

BACKGROUND OF THE INVENTION

[0002] Fine patterns, for example, for color filters for liquid crystaldisplays have been formed by photolithography, printing,electrodeposition, or the like. Among these pattern formation methods,photolithography is advantageous in accuracy and quality of appearance.The photolithography, which can realize wiring of a pattern with highaccuracy, is also used in the formation of conductor patterns in printedwiring boards.

[0003] In an example of the production of a color filter byphotolithography, a photosensitive resist is coated on a thin film of ametal, such as chromium, formed, for example, by sputtering or vapordeposition, exposure through a photomask and development are carried outto prepare a resist pattern, and the thin metal film is patterned byetching using the resist pattern as a mask to form a black matrix. Next,a color pigment-containing photosensitive resist is coated, followed byexposure through a photomask and development to form a colored layer fora color filter. On the other hand, in the case of a printed wiringboard, a photosensitive resist pattern is formed on a copper plating,and the copper plating is etched using the photosensitive resist patternas a mask to produce a conductor pattern.

[0004] The above-described conventional fine pattern formation byphotolithography, such as pattern formation for a color filter andconductor pattern formation, however, disadvantageously suffers from acomplicated process, which is an obstacle to a reduction in productioncost.

DISCLOSURE OF THE INVENTION

[0005] Under the above circumstances, the present invention has beenmade, and it is an object of the present invention to provide anapparatus for fine pattern formation, which can form a fine pattern withhigh accuracy by direct writing of a pattern with ink, a productionprocess of fine nozzles provided in the apparatus for fine patternformation, and a method for fine pattern formation.

[0006] In order to attain the above object, according to one aspect ofthe present invention, there is provided an apparatus for fine patternformation comprising: a silicon substrate; a plurality of fine holeswhich extend through the silicon substrate from the surface of thesilicon substrate to the back surface of the silicon substrate and havea silicon oxide layer on the wall surface thereof; fine nozzles whichare protruded, integrally with the silicon oxide layer, on the backsurface side of the silicon substrate from each opening of the fineholes; a silicon nitride layer provided on the surface and side of thesilicon substrate; a support member provided on the surface side of thesilicon substrate; an ink passage for supplying ink to the opening ofeach fine hole on the surface side of the silicon substrate; and an inksupplying device connected to the ink passage.

[0007] In this apparatus, preferably, the diameter of the openings inthe fine nozzles is in the range of 1 to 100 μm in a variation within ±1μm and the fine nozzles are provided at a pitch in the range of 2 to1000 μm.

[0008] According to another aspect of the present invention, there isprovided an apparatus for fine pattern formation, comprising: a siliconsubstrate; a plurality of fine nozzles protruded from the back surfaceof the silicon substrate; a plurality of fine holes which extend at finenozzle formed sites through the silicon substrate from the surface ofthe silicon substrate to the back surface of the silicon substrate andhave a silicon oxide layer on the wall surface thereof; a support memberprovided on the surface side of the silicon substrate; an ink passagefor supplying ink to the opening of each fine hole on the surface sideof the silicon substrate; and an ink supplying device connected to theink passage, said fine nozzles each comprising a nozzle base providedintegrally with the silicon substrate, an inner surface layer of siliconoxide provided on the inner wall surface of nozzle bases incommunication with the fine holes, and an end face layer of siliconoxide provided integrally with the inner surface layer of silicon oxideso as to cover the front end face of the nozzle bases.

[0009] In this apparatus, preferably, the diameter of the openings inthe fine nozzles is in the range of 1 to 100 μm in a variation within ±1μm and the fine nozzles are provided at a pitch in the range of 4 to1000 μm.

[0010] In the above apparatuses for fine pattern formation, preferably,the protrusion length of the fine nozzles is in the range of 1 to 150μm.

[0011] In the above apparatuses for fine pattern formation, preferably,the fine holes in their openings on the surface side of the siliconsubstrate are in the form of tapered concaves which have been widenedtoward the surface side of the silicon substrate. Alternatively, in theabove apparatuses for fine pattern formation, preferably, the fine holesin their openings on the surface side of the silicon substrate are inthe form of multistaged concaves which have been widened toward thesurface side of the silicon substrate.

[0012] In the above apparatuses for fine pattern formation, preferably,fine holes are divided into two or more groups and ink passages areprovided separately from each other or one another for respective finehole groups.

[0013] According to still another aspect of the present invention, thereis provided a process for producing a plurality of fine nozzles, formedof silicon oxide, protruded from one surface of a silicon substrate andin communication with fine holes which extend through the siliconsubstrate and have a silicon oxide layer on the wall surface thereof,said process comprising: a first step of providing a silicon substratehaving on its whole surface a silicon nitride layer and forming a maskpattern having a plurality of fine openings on the silicon nitride layerin its portion located on one surface of the silicon substrate; a secondstep of forming through fine holes in the silicon substrate by deepetching using the mask pattern as a mask; a third step of removing themask pattern and oxidizing the inside of the through fine holes of thesilicon substrate to form a silicon oxide layer; and a fourth step ofremoving a part of the silicon nitride layer and a part of the siliconsubstrate from one surface of the silicon substrate by dry etching toexpose the silicon oxide layer by a predetermined length, therebyforming fine nozzles.

[0014] In the fourth step, preferably, etching is started with thesurface from which the mask pattern has been removed.

[0015] According to a further aspect of the present invention, there isprovided a process for producing a plurality of fine nozzles protrudedfrom one surface of a silicon substrate, said fine nozzles comprising anozzle base, provided integrally with the silicon substrate, and asilicon oxide end face layer covering the front end face of the nozzlebase, said nozzle base being in communication with fine holes, whichextend through the silicon substrate and have a silicon oxide layer onthe wall surface thereof, and having a silicon oxide inner surface layeron its inner wall surface, said process comprising: a first step ofproviding a silicon substrate having on its whole surface a siliconnitride layer and patterning the silicon nitride layer in its portionlocated on one surface of the silicon substrate to form a pattern havinga plurality of small openings; a second step of forming a mask thin filmso as to cover the pattern of the silicon nitride layer and patterningthe mask thin film to form a mask pattern having fine openings locatedwithin the small openings; a third step of forming through fine holes inthe silicon substrate by deep etching using the mask pattern as a mask;a fourth step of removing the mask pattern and oxidizing sites withinthe through fine holes in the silicone substrate and sites exposedwithin the small openings to form a silicon oxide layer; a fifth step ofremoving the silicon nitride layer and removing a part of the siliconsubstrate by dry etching using the silicon oxide layer as a mask fromthe surface side, on which the silicon oxide layer has been formed, toform nozzle bases having a predetermined length, thereby forming finenozzles.

[0016] According to a still further aspect of the present invention,there is provided a process for producing a plurality of fine nozzles,formed of silicon oxide, protruded from one surface of a siliconsubstrate and in communication with fine holes which extend through thesilicon substrate and have a silicon oxide layer on the wall surfacethereof, said process comprising: a first step of providing a siliconsubstrate of <100> surface crystal orientation having on its wholesurface a silicon nitride layer and patterning the silicon nitride layerin its portion located on one surface side of the silicon substrate toform a pattern having a plurality of openings for taper; a second stepof etching the surface of the silicon substrate by crystallographicallyanisotropic etching using the silicon nitride layer as a mask to formtapered concaves; a third step of forming a mask thin film on bothsurfaces of the silicon substrate and patterning the mask thin film inits portion located on the surface of the silicon substrate remote fromthe tapered concaves to form a mask pattern having fine openings suchthat the center of each opening substantially conforms to the center ofeach tapered concave through the silicon substrate; a fourth step offorming through fine holes in the silicon substrate by deep etchingusing, as a mask, the mask pattern and the mask thin film; a fifth stepof removing the mask pattern and the mask thin film and oxidizing siteswithin the through fine holes in the silicone substrate and sitesexposed within the tapered concaves to form a silicon oxide layer; and asixth step of removing a part of the silicon nitride layer and a part ofthe silicon substrate by dry etching from the surface side of thesilicon substrate remote from the tapered concaves to expose the siliconoxide layer by a predetermined length, thereby forming fine nozzles.

[0017] According to another aspect of the present invention, there isprovided a process for producing a plurality of fine nozzles protrudedfrom one surface of a silicon substrate, said fine nozzles comprising anozzle base, provided integrally with the silicon substrate, and asilicon oxide end face layer covering the front end face of the nozzlebase, said nozzle base being in communication with fine holes, whichextend through the silicon substrate and have a silicon oxide layer onthe wall surface thereof, and having a silicon oxide inner surface layeron its inner wall surface, said process comprising: a first step ofproviding a silicon substrate of <100> surface crystal orientationhaving on its whole surface a silicon nitride layer and patterning thesilicon nitride layer in its portion located on one surface side of thesilicon substrate to form a pattern having a plurality of openings fortaper; a second step of etching the surface of the silicon substrate bycrystallographically anisotropic etching using the silicon nitride layeras a mask to form tapered concaves; a third step of patterning thesilicon nitride layer in its portion located on the surface side of thesilicon substrate remote from the tapered concaves to form a patternhaving small openings such that the center of each opening substantiallyconforms to the center of each tapered concave through the siliconsubstrate; a fourth step of forming a mask thin film on both surfaces ofthe silicon substrate and patterning the mask thin film in its portionlocated on the surface side of the silicon substrate remote from taperedconcaves to form a mask pattern having fine openings located within thesmall openings; a fifth step of forming through fine holes in thesilicon substrate by deep etching using, as a mask, the mask pattern andthe mask thin film; a sixth step of removing the mask pattern and themask thin film and oxidizing sites within the through fine holes in thesilicone substrate, sites exposed within the small openings, and sitesexposed within the tapered concaves to form a silicon oxide layer; and aseventh step of removing the silicon nitride layer and removing a partof the silicon substrate by dry etching using the silicon oxide layer asa mask from the surface side of the silicon substrate remote from thetapered concaves to form nozzle bases having a predetermined length,thereby forming fine nozzles.

[0018] According to still another aspect of the present invention, thereis provided a process for producing a plurality of fine nozzles, formedof silicon oxide, protruded from one surface of a silicon substrate andin communication with fine holes which extend through the siliconsubstrate and have a silicon oxide layer on the wall surface thereof,said process comprising: a first step of providing a silicon substratehaving on its whole surface a silicon nitride layer, forming a maskpattern having a plurality of fine openings on the silicon nitride layerin its portion located on one surface of the silicon substrate, andforming, on the silicon nitride layer on the other surface of thesilicon substrate, a mask pattern having wide openings such that thecenter of each wide opening substantially conforms to the center of eachfine opening through the silicon substrate; a second step of formingfine holes having predetermined depth in the silicon substrate by deepetching using the mask pattern having fine openings as a mask; a thirdstep of forming wide concaves in the silicon substrate by deep etchingusing the mask pattern having wide openings as a mask in such a mannerthat the openings of the fine holes are exposed within the wideconcaves, thereby forming multistaged concaves; a fourth step ofremoving the mask pattern and oxidizing sites within the fine holes ofthe silicon substrate and sites exposed within the wide concaves to forma silicon oxide layer; and a fifth step of removing a part of thesilicon nitride layer and a part of the silicon substrate from thesurface of the silicon substrate remote from the wide concaves by dryetching to expose the silicon oxide layer by a predetermined length,thereby forming fine nozzles.

[0019] According to a further aspect of the present invention, there isprovided a process for producing a plurality of fine nozzles protrudedfrom one surface of a silicon substrate, said fine nozzles comprising anozzle base, provided integrally with the silicon substrate, and asilicon oxide end face layer covering the front end face of the nozzlebase, said nozzle base being in communication with fine holes, whichextend through the silicon substrate and have a silicon oxide layer onthe wall surface thereof, and having a silicon oxide inner surface layeron its inner wall surface, said process comprising: a first step ofproviding a silicon substrate having on its whole surface a siliconnitride layer and patterning the silicon nitride layer in its portionlocated on one surface of the silicon substrate to form a pattern havinga plurality of small openings; a second step of forming a mask thin filmso as to cover the pattern of the silicon nitride layer and thenpatterning the mask thin film to form a mask pattern having fineopenings located within the small openings, and, in addition, patterningthe mask thin film on the other surface to form a mask pattern havingwide openings such that the center of each wide opening substantiallyconforms to the center of each fine opening through the siliconsubstrate; a third step of forming fine holes having predetermined depthin the silicon substrate by deep etching using the mask pattern havingfine openings as a mask; a fourth step of forming wide concaves in thesilicon substrate by deep etching using the mask pattern having wideopenings as a mask in such a manner that the openings of the fine holesare exposed within the wide concaves, thereby forming multistagedconcaves; a fifth step of removing the mask pattern and oxidizing siteswithin the fine holes of the silicon substrate, sites exposed within thewide concaves, and sites exposed within the small openings to form asilicon oxide layer; and a sixth step of removing the silicon nitridelayer and removing a part of the silicon substrate by dry etching usingthe silicon oxide layer as a mask from the surface of the siliconsubstrate remote from the wide concaves to form nozzle bases having apredetermined length, thereby forming fine nozzles.

[0020] According to the above invention, ink supplied to the fine holesin the silicon substrate can be ejected through the fine nozzles anddeposited onto a pattern object to directly write a pattern on thepattern object, and the amount of ink deposited can be varied as desiredby varying the amount of ink supplied.

[0021] Furthermore, in order to attain the above object, according to afurther aspect of the present invention, there is provided an apparatusfor fine pattern formation comprising: a silicon substrate; a pluralityof fine holes which extend through the silicon substrate from thesurface of the silicon substrate to the back surface of the siliconsubstrate and have a silicon oxide layer on the wall surface thereof;fine nozzles which are protruded, integrally with the silicon oxidelayer, on the back surface side of the silicon substrate from eachopening of the fine holes; a reinforcing layer provided at least on thefront end face and outer face of the fine nozzles; a support memberprovided on the surface side of the silicon substrate; an ink passagefor supplying ink to the opening of each fine hole on the surface sideof the silicon substrate; and an ink supplying device connected to theink passage.

[0022] In the above apparatus for fine pattern formation, preferably,the thickness of the reinforcing layer is at least twice the thicknessof the fine nozzles.

[0023] In the above apparatus for fine pattern formation, preferably,the reinforcing layer is formed of any one of silicon oxide andphosphorus silicon glass.

[0024] In the above apparatus for fine pattern formation, preferably,the fine nozzles have an opening diameter in the range of 1 to 100 μmand are provided at a pitch in the range of 4 to 1000 μm. Alternatively,in the above apparatus for fine pattern formation, preferably, the finenozzles have a projection length in the range of 1 to 400 μm.

[0025] In the above apparatus for fine pattern formation, preferably,the fine holes in their openings on the surface side of the siliconsubstrate are in the form of tapered concaves which have been widenedtoward the surface side of the silicon substrate. Alternatively, in theabove apparatus for fine pattern formation, preferably, the fine holesin their openings on the surface side of the silicon substrate are inthe form of multistaged concaves which have been widened toward thesurface side of the silicon substrate.

[0026] In the above apparatus for fine pattern formation, preferably,the fine holes are divided into two or more groups and ink passages areprovided separately from each other or one another for respective finehole groups.

[0027] In the above apparatus for fine pattern formation, preferably, awater-repellent layer is provided at least on the reinforcing layer,which is provided on the outer face of the fine nozzles, and on the backsurface side of the silicon substrate.

[0028] In the above apparatus for fine pattern formation, preferably,the water-repellent layer is formed of fluorocarbon.

[0029] According to the present invention, the provision of thereinforcing layer in the fine nozzles can enhance the mechanicalstrength of the fine nozzles, ink supplied to the fine holes in thesilicon substrate can be ejected through the fine nozzles and depositedon the pattern object to directly write a pattern, and the amount of inkdeposited can be varied as desired by varying the amount of inksupplied.

[0030] Further, in order to attain the above object, according toanother aspect of the present invention, there is provided an apparatusfor fine pattern formation, comprising: a silicon substrate; a pluralityof fine holes provided so as to extend through the silicon substratefrom the surface of the silicon substrate to the back surface of thesilicon substrate; a main electrode provided on the surface side of thesilicon substrate; a counter electrode provided on the back surface sideof the silicon substrate while leaving a predetermined space between themain electrode and the counter electrode; a support member provided onthe surface side of the silicon substrate; an ink passage for supplyingink to openings in the fine holes on the surface side of the siliconsubstrate; and an ink supplying device connected to the ink passage.

[0031] In the above apparatus for fine pattern formation, preferably,nozzles are protruded from the openings of the fine holes on the backsurface side of the silicon substrate.

[0032] In the above apparatus for fine pattern formation, preferably,the wall surface of the fine holes has a silicon oxide layer and thenozzles are formed of silicon oxide.

[0033] In the above apparatus for fine pattern formation, preferably,the counter electrode is in a drum or flat plate form.

[0034] In the above apparatus for fine pattern formation, preferably,the fine holes have an opening diameter in the range of 1 to 100 μm andare provided at a pitch in the range of 2 to 1000 μm.

[0035] In the above apparatus for fine pattern formation, preferably,the nozzles have a protrusion length in the range of 10 to 400 μm.

[0036] In the above apparatus for fine pattern formation, preferably,the fine holes in their openings on the surface side of the siliconsubstrate are in the form of tapered concaves which have been widenedtoward the surface side of the silicon substrate. Alternatively, in theabove apparatus for fine pattern formation, preferably, the fine holesin their openings on the surface side of the silicon substrate are inthe form of multistaged concaves which have been widened toward thesurface side of the silicon substrate.

[0037] In the above apparatus for fine pattern formation, preferably,the fine holes are divided into two or more groups and ink passages areprovided separately from each other or one another for respective finehole groups. Alternatively, in the above apparatus for fine patternformation, preferably, main electrodes are separately provided forrespective fine hole groups.

[0038] According to still another aspect of the present invention, thereis provided a method for fine pattern formation, comprising the step of:while relatively scanning any one of the apparatuses for fine patternformation and a pattern object in a predetermined direction,continuously or intermittently ejecting ink supplied at low pressurefrom the ink passage onto the pattern object through the fine holes insuch a state that a voltage is applied to the main electrode in theapparatus for fine pattern formation, whereby a stripe pattern or a dotpattern is formed.

[0039] In the above method for fine pattern formation, preferably,stripes constituting the pattern are formed by supplying ink through aplurality of fine holes arranged on an identical line along the scanningdirection.

[0040] According to a further aspect of the present invention, there isprovided a method for fine pattern formation, comprising the steps of:disposing any one of the above apparatuses for fine pattern formation ata predetermined position of a pattern object; and ejecting a givenamount of ink supplied at low pressure from the ink passage onto thepattern object through the fine holes in such a state that a voltage isapplied to the main electrode of the apparatus for fine patternformation, whereby a pattern is formed.

[0041] In the above method for fine pattern formation, preferably, thevoltage applied to the main electrode is regulated to control inkejection width and the amount of ink ejected.

[0042] According to the present invention, supplied ink can be ejectedthrough the fine holes in the silicon substrate by an electric fieldformed between the main electrode and the counter electrode and a lowpressure applied at the time of supply of the ink and can be depositedonto a pattern object to directly write a pattern, and the amount of inkdeposited can be varied as desired by varying the field strength and theink supply pressure to control ink ejection width and the amount of inkejected. As used herein, the term “ink” generally refers to a liquidcomposition comprising a colorant, such as a dye or a pigment, and abinder or a vehicle. For example, in display members or circuitformation applications, however, the ink widely embraces pastescontaining metallic or magnetic fine particles or ceramic or other fineparticles, and liquid compositions containing a resin or a phosphormaterial or an organic EL material, and photoresists.

BRIEF DESCRIPTION OF THE DRAWINGS

[0043]FIG. 1 is a schematic cross-sectional view showing one embodimentof the apparatus for fine pattern formation according to the presentinvention;

[0044]FIG. 2 is a schematic cross-sectional view showing anotherembodiment of the apparatus for fine pattern formation according to thepresent invention;

[0045]FIG. 3 is a schematic cross-sectional view showing a still anotherembodiment of the apparatus for fine pattern formation according to thepresent invention;

[0046]FIG. 4 is a schematic cross-sectional view showing a furtherembodiment of the apparatus for fine pattern formation according to thepresent invention;

[0047]FIG. 5 is a schematic cross-sectional view showing a still furtherembodiment of the apparatus for fine pattern formation according to thepresent invention;

[0048]FIG. 6 is a schematic cross-sectional view showing anotherembodiment of the apparatus for fine pattern formation according to thepresent invention;

[0049]FIG. 7 is a schematic cross-sectional view showing still anotherembodiment of the apparatus for fine pattern formation according to thepresent invention;

[0050]FIG. 8 is a bottom view of the apparatus for fine patternformation shown in FIG. 7;

[0051]FIG. 9 is a diagram showing a further embodiment of the apparatusfor fine pattern formation according to the present invention, whereinFIG. 9 (A) is a schematic cross-sectional view and FIG. 9 (B) a bottomview.

[0052]FIG. 10 is a transverse sectional view taken on line A-A of asupport member in the apparatus for fine pattern formation shown in FIG.9;

[0053]FIG. 11 is a transverse sectional view taken on line B-B of asupport member in the apparatus for fine pattern formation shown in FIG.9;

[0054]FIG. 12 is a perspective view showing ink passages in theapparatus for fine pattern formation shown in FIG. 9;

[0055]FIG. 13 is a plan view showing a still further embodiment of theapparatus for fine pattern formation according to the present invention;

[0056]FIG. 14 is a perspective view showing one embodiment of finepattern formation using the apparatus for fine pattern formationaccording to the present invention;

[0057]FIG. 15 is a perspective view showing another embodiment of finepattern formation using the apparatus for fine pattern formationaccording to the present invention;

[0058]FIG. 16 is a process diagram illustrating one embodiment of theproduction process of fine nozzles according to the present invention;

[0059]FIG. 17 is a process diagram illustrating another embodiment ofthe production process of fine nozzles according to the presentinvention;

[0060]FIG. 18 is a process diagram illustrating still another embodimentof the production process of fine nozzles according to the presentinvention;

[0061]FIG. 19 is a process diagram illustrating a further embodiment ofthe production process of fine nozzles according to the presentinvention;

[0062]FIG. 20 is a process diagram illustrating a still furtherembodiment of the production process of fine nozzles according to thepresent invention;

[0063]FIG. 21 is a process diagram illustrating another embodiment ofthe production process of fine nozzles according to the presentinvention;

[0064]FIG. 22 is a process diagram illustrating still another embodimentof the production process of fine nozzles according to the presentinvention;

[0065]FIG. 23 is a process diagram illustrating a further embodiment ofthe production process of fine nozzles according to the presentinvention;

[0066]FIG. 24 is a process diagram illustrating a still furtherembodiment of the production process of fine nozzles according to thepresent invention;

[0067]FIG. 25 is a process diagram illustrating another embodiment ofthe production process of fine nozzles according to the presentinvention;

[0068]FIG. 26 is a schematic cross-sectional view showing one embodimentof the apparatus for fine pattern formation according to the presentinvention;

[0069]FIG. 27 is a partially enlarged cross-sectional view of a portionaround the front end of fine nozzles in the apparatus for fine patternformation shown in FIG. 26;

[0070]FIG. 28 is a schematic cross-sectional view showing anotherembodiment of the apparatus for fine pattern formation according to thepresent invention;

[0071]FIG. 29 is a schematic cross-sectional view showing still anotherembodiment of the apparatus for fine pattern formation according to thepresent invention;

[0072]FIG. 30 is a schematic cross-sectional view showing a furtherembodiment of the apparatus for fine pattern formation according to thepresent invention;

[0073]FIG. 31 is a bottom view of the apparatus for fine patternformation shown in FIG. 5;

[0074]FIG. 32 is a diagram showing another embodiment of the apparatusfor fine pattern formation according to the present invention, whereinFIG. 32 (A) is a schematic cross-sectional view and FIG. 32 (B) a bottomview;

[0075]FIG. 33 is a transverse sectional view taken on line A-A of asupport member in the apparatus for fine pattern formation shown in FIG.32;

[0076]FIG. 34 is a transverse sectional view taken on line B-B of asupport member in the apparatus for fine pattern formation shown in FIG.32;

[0077]FIG. 35 is a perspective view showing ink passages in theapparatus for fine pattern formation shown in FIG. 32;

[0078]FIG. 36 is a plan view showing a further embodiment of theapparatus for fine pattern formation according to the present invention;

[0079]FIG. 37 is a process diagram illustrating one embodiment of theproduction of the apparatus for fine pattern formation according to thepresent invention;

[0080]FIG. 38 is a process diagram illustrating one embodiment of theproduction of the apparatus for fine pattern formation according to thepresent invention;

[0081]FIG. 39 is a process diagram illustrating another embodiment ofthe production of the apparatus for fine pattern formation according tothe present invention;

[0082]FIG. 40 is a process diagram illustrating still another embodimentof the production of the apparatus for fine pattern formation accordingto the present invention;

[0083]FIG. 41 is a process diagram illustrating a further embodiment ofthe production of the apparatus for fine pattern formation according tothe present invention;

[0084]FIG. 42 is a process diagram illustrating a still furtherembodiment of the production of the apparatus for fine pattern formationaccording to the present invention;

[0085]FIG. 43 is a process diagram illustrating another embodiment ofthe production of the apparatus for fine pattern formation according tothe present invention;

[0086]FIG. 44 is a process diagram illustrating still another embodimentof the production of the apparatus for fine pattern formation accordingto the present invention;

[0087]FIG. 45 is a process diagram illustrating a further embodiment ofthe production of the apparatus for fine pattern formation according tothe present invention;

[0088]FIG. 46 is a perspective view showing one embodiment of finepattern formation using the apparatus for fine pattern formationaccording to the present invention;

[0089]FIG. 47 is a perspective view showing another embodiment of finepattern formation using the apparatus for fine pattern formationaccording to the present invention;

[0090]FIG. 48 is a schematic cross-sectional view showing one embodimentof the apparatus for fine pattern formation according to the presentinvention;

[0091]FIG. 49 is a plan view illustrating a main electrode provided onthe surface side of a silicon substrate, in such a state that a supportmember has been removed;

[0092]FIG. 50 is a schematic cross-sectional view showing anotherembodiment of the apparatus for fine pattern formation according to thepresent invention;

[0093]FIG. 51 is a rear view illustrating a main electrode in a frameform provided on the back surface side of a silicon substrate;

[0094]FIG. 52 is a schematic cross-sectional view showing still anotherembodiment of the apparatus for fine pattern formation according to thepresent invention;

[0095]FIG. 53 is a schematic cross-sectional view showing a furtherembodiment of the apparatus for fine pattern formation according to thepresent invention;

[0096]FIG. 54 is a schematic cross-sectional view showing a stillfurther embodiment of the apparatus for fine pattern formation accordingto the present invention;

[0097]FIG. 55 is a schematic cross-sectional view showing anotherembodiment of the apparatus for fine pattern formation according to thepresent invention;

[0098]FIG. 56 is a bottom view of the apparatus for fine patternformation shown in FIG. 55;

[0099]FIG. 57 is a diagram showing a further embodiment of the apparatusfor fine pattern formation according to the present invention, whereinFIG. 57 (A) is a schematic cross-sectional view and FIG. 57 (B) a bottomview;

[0100]FIG. 58 is a transverse sectional view taken on line A-A of asupport member in the apparatus for fine pattern formation shown in FIG.57;

[0101]FIG. 59 is a transverse sectional view taken on line B-B of asupport member in the apparatus for fine pattern formation shown in FIG.57;

[0102]FIG. 60 is a perspective view showing ink passages in theapparatus for fine pattern formation shown in FIG. 7;

[0103]FIG. 61 is a plan view showing a still further embodiment of theapparatus for fine pattern formation according to the present invention;

[0104]FIG. 62 is a process diagram showing one embodiment of theproduction of the apparatus for fine pattern formation according to thepresent invention;

[0105]FIG. 63 is a process diagram showing one embodiment of theproduction of the apparatus for fine pattern formation according to thepresent invention;

[0106]FIG. 64 is a process diagram showing another embodiment of theproduction of the apparatus for fine pattern formation according to thepresent invention;

[0107]FIG. 65 is a process diagram showing still another embodiment ofthe production of the apparatus for fine pattern formation according tothe present invention;

[0108]FIG. 66 is a process diagram showing a further embodiment of theproduction of the apparatus for fine pattern formation according to thepresent invention;

[0109]FIG. 67 is a process diagram showing still further embodiment ofthe production of the apparatus for fine pattern formation according tothe present invention;

[0110]FIG. 68 is a perspective view showing one embodiment of the methodfor fine pattern formation according to the present invention; and

[0111]FIG. 69 is a perspective view showing another embodiment of themethod for fine pattern formation according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0112] Embodiment of the present invention will be described withreference to the accompanying drawings.

I-1 Apparatus for Fine Pattern Formation First Embodiment

[0113]FIG. 1 is a schematic cross-sectional view showing an embodimentof the apparatus for fine pattern formation according to the presentinvention. In FIG. 1, an apparatus 1 for fine pattern formationcomprises a silicon substrate 2, fine nozzles 5 protruded on the backsurface 2B side of the silicon substrate 2, a silicon nitride layer 6provided on a surface 2A and a side face 2C of the silicon substrate 2,a support member 7, an ink passage 8 for supplying ink to a spacebetween the silicon substrate 2 and the support member 7, and an inksupplying device 9 connected to the ink passage 8.

[0114] The silicon substrate 2 has a plurality of fine holes 3 whichextend through the silicon substrate 2 from the surface 2A side to theback surface 2B side. Openings 3 a on the surface 2A side of the fineholes 3 are exposed to the space defined by the silicon substrate 2 andthe support member 7. The silicon substrate 2 is preferably formed of asingle crystal of silicon, and the thickness of the silicon substrate 2is preferably about 200 to 500 μm. Since the silicon substrate 2 has alow coefficient of linear expansion of about 2.6×10⁻⁶/K, a change inshape upon a temperature change is very small.

[0115] The fine holes 3 are cylindrical spaces which are circular in atransverse section perpendicular to the axial direction (a sectionparallel to the surface 2A of the silicon substrate 2) and arerectangular in a longitudinal section along the axial direction (asection perpendicular to the surface 2A of the silicon substrate 2) Asilicon oxide layer 4 is provided on the wall surface of the fine holes3. The thickness of the silicon oxide layer 4 is generally about 5000 to10000 angstroms. In the embodiment shown in the drawing, the thicknessof the silicon substrate 2, the inner diameter of the fine holes 3, thenumber of fine holes, the pitch of the fine holes and the like aresimplified for the explanation of the construction of the apparatus. Theinner diameter of the fine holes 3 may be properly set in the range ofabout 1 to 100 μm, and the aspect ratio of the fine holes 3 may beproperly set in the range of about 1 to 100. The number of the fineholes 3 and the pitch of the fine holes 3 may be properly set accordingto the form of pattern formed by the apparatus 1 for fine patternformation, the method for pattern formation and the like. The pitch ofthe fine holes 3 is preferably about 1 μm at the smallest.

[0116] The transverse sectional form of the fine holes 3 may be, inaddition to the above-described circular form, for example, anelliptical or polygonal form or a special form. Further, the fine holes3 may be a combination of two or more fine holes which are differentfrom each other in transverse sectional form. When the fine holes 3 areelliptical or rectangular in transverse sectional form, the innerdiameter in the longitudinal direction may be properly set in the rangeof 5 to 500 μm. The inner diameter of the fine holes 3 is substantiallyeven in the axial direction, and the variation in the inner diameter isgenerally within ±1 μm.

[0117] The fine nozzles 5 are formed of silicon oxide, are providedintegrally with the silicon oxide layer 4 provided on the wall surfaceof the fine holes 3, and are in communication with the fine holes 3. Thethickness of the fine nozzles 5 may be properly set in the range of 5000to 10000 angstroms, the opening diameter (inner diameter) may beproperly set in the range of 1 to 100 μm, and the protrusion level maybe properly set in the range of 1 to 150 μm. The opening diameter of theplurality of fine nozzles 5 is substantially even, and the variation inthe opening diameter is generally within ±1 μm. The provision of suchfine nozzles 5 can prevent ink, ejected from the fine holes 3, frombeing deposited on the back surface 2B side of the silicon substrate 2.

[0118] The silicon nitride layer 6 functions as a mask for selectiveoxidation (LOCOS) and to impart high electrical insulating properties tothe silicon substrate 2, and the thickness of the silicon nitride layer6 may be properly set in the range of 200 to 3000 angstroms.

[0119] The support member 7 is provided on the surface 2A side of thesilicon substrate 2, for supporting the silicon substrate 2. In theembodiment shown in the drawing, the support member 7 comprises: a base7 a, which, as with the silicon substrate 2, is flat; a flange portion 7b provided on the periphery of the base 7 a; and an opening 7 c providedat the center of the base 7 a. The support member 7 is fixed to theperipheral portion of the surface 2A side of the silicon substrate 2 bythe flange portion 7 b. This can provide a space for supplying ink to aportion between the silicon substrate 2 and the support member 7. Thefixation of the support member 7 to the silicon substrate 2 throughheat-resistant glass, such as Pyrex glass (tradename) (not shown), canimprove the working efficiency of later steps in the production of theapparatus for fine pattern formation.

[0120] This support member 7 is preferably formed of a material having acoefficient of linear expansion in the range of one-tenth of thecoefficient of linear expansion of the silicon substrate 2 to 10 timesthe coefficient of linear expansion of the silicon substrate 2, forexample, Pyrex glass (tradename: Corning #7740, coefficient of linearexpansion =3.5×10⁻⁶/K) or SUS 304 (coefficient of linear expansion=17.3×10⁻⁶/K). When these materials are used, the level of a distortioncaused between the silicon substrate 2 and the support member 7 uponexposure to heat is very small. By virtue of this, the flatness of thesilicon substrate 2 is maintained, and a pattern having high positionalaccuracy can be formed.

[0121] The ink passage 8 is connected to the opening 7 c of the supportmember 7, and the other end of the ink passage 8 is connected to an inksupplying device 9. In the embodiment shown in the drawing, only one inkpassage 8 in a pipe form is connected. In this case, a construction mayalso be adopted wherein a plurality of openings 7 c are provided, thenumber of the openings being determined by taking into consideration,for example, the size of the apparatus 1 for fine pattern formation andthe evenness of ink flow pressure, and the ink passage 8 is connected toeach opening 7 c. The support member 7 and the silicon substrate 2 maybe fabricated so that the ink passage is provided within the supportmember 7 and/or the silicon substrate 2.

[0122] The ink supplying device 9 is not particularly limited, and anyof a continuous supply pump, a constant rate supply pump and the likemay be used as the ink supplying device 9 and may be properly selectedaccording to the application of the apparatus 1 for fine patternformation.

[0123] In this apparatus 1 for fine pattern formation according to thepresent invention, ink can be ejected through the plurality of finenozzles 5 on the back surface of the silicon substrate 2 in a very smallamount with high accuracy at substantially even ejection width, and, atthe same time, the deposition of ink onto the back surface of thesilicon substrate 2 can be prevented. The amount of ink ejected can beset as desired by varying the amount of ink supplied through the controlof the ink supplying device 9. Therefore, a pattern can be stably formedby direct writing with high accuracy on a pattern object.

Second Embodiment

[0124]FIG. 2 is a schematic cross-sectional view showing anotherembodiment of the apparatus for fine pattern formation according to thepresent invention. As shown in FIG. 2, an apparatus 11 for fine patternformation comprises a silicon substrate 12, fine nozzles 15 protruded onthe back surface 2B side of the silicon substrate 12, a support member17, an ink passage 18 for supplying ink to a space between the siliconsubstrate 12 and the support member 17, and an ink supplying device 19connected to the ink passage 18.

[0125] The silicon substrate 12 has a plurality of fine holes 13 whichextend through the silicon substrate 12 from the surface 12A side to theback surface 12B side. Openings 13 a on the surface 12A side of the fineholes 13 are exposed to the space defined by the silicon substrate 12and the support member 17. The silicon substrate 12 may be formed of thesame material as in the silicon substrate 2, and the thickness of thesilicon substrate 12 may also be set in the same range as in the siliconsubstrate 2.

[0126] The fine holes 13 are cylindrical spaces which are circular in atransverse section perpendicular to the axial direction (a sectionparallel to the surface 12A of the silicon substrate 12) and arerectangular in a longitudinal section along the axial direction (asection perpendicular to the surface 12A of the silicon substrate 12). Asilicon oxide layer 14 is provided on the wall surface of the fine holes13. The thickness of the silicon oxide layer 14 is generally about 5000to 10000 angstroms. In the embodiment shown in the drawing, thethickness of the silicon substrate 12, the inner diameter of the fineholes 13, the number of fine holes 13, the pitch of the fine holes 13and the like are simplified for the explanation of the construction ofthe apparatus. The inner diameter of the fine holes 13 may be properlyset in the range of about 1 to 100 μm, and the aspect ratio of the fineholes 13 may be properly set in the range of about 1 to 100. The numberof the fine holes 13 and the pitch of the fine holes 13 may be properlyset according to the form of pattern formed by the apparatus 11 for finepattern formation, the method for pattern formation and the like. Thepitch of the fine holes 13 is preferably about 4 μm at the smallest.

[0127] The transverse sectional form of the fine holes 13 may be, inaddition to the above-described circular form, for example, anelliptical or polygonal form or a special form. Further, the fine holes13 may be a combination of two or more fine holes which are differentfrom each other in transverse sectional form. When the fine holes areelliptical or rectangular in transverse sectional form, the innerdiameter in the longitudinal direction may be properly set in the rangeof 5 to 500 μm. The inner diameter of the fine holes 13 is substantiallyeven in the axial direction, and the variation in the inner diameter isgenerally within ±1 μm.

[0128] The fine nozzles 15 each comprise: a nozzle base 15 a providedintegrally with the silicon substrate 12; an inner surface layer 15 b ofsilicon oxide provided on the inner wall surface of the nozzle base 15 ain communication with the fine hole 13; and an end face layer 15 c ofsilicon oxide provided so as to cover the front end face of the nozzlebase 15 a. The inner surface layer 15 b of silicon oxide and the endface layer 15 c of silicon oxide are provided integrally with thesilicon oxide layer 14 provided on the wall surface of the fine hole 13.The outer diameter of the nozzle bases 15 a may be properly set in therange of 3 to 150 μm, and the wall thickness of the nozzle bases 15 amay be properly set in the range of 1 to 25 μm. The thickness of theinner surface layer 15 b of silicon oxide and the thickness of the endface layer 15 c of silicon oxide may be properly set in the range of5000 to 10000 angstroms, the opening diameter of the fine nozzles 15(the inner diameter of the inner surface layer 15 b of silicon oxide)may be properly set in the range of 1 to 100 μm, and the protrusionlevel of the fine nozzles 15 (the height of the nozzle bases 15 a) maybe properly set in the range of 1 to 150 μm. The opening diameter of theplurality of fine nozzles 15 is substantially even, and the variation inthe opening diameter is generally within ±1 μm. The provision of suchfine nozzles 15 can prevent ink, ejected from the fine holes 13, frombeing deposited on the back surface 12B side of the silicon substrate12.

[0129] The support member 17 is provided on the surface 12A side of thesilicon substrate 12, for supporting the silicon substrate 12. In theembodiment shown in the drawing, as with the support member 7 describedabove, the support member 17 comprises: a base 17 a, which, as with thesilicon substrate 12, is flat; a flange portion 17 b provided on theperiphery of the base 17 a; and an opening 17 c provided at the centerof the base 17 a. The support member 17 is fixed to the peripheralportion of the surface 12A side of the silicon substrate 12 by theflange portion 17 b. This can provide a space for supplying ink to aportion between the silicon substrate 12 and the support member 17. Thefixation of the support member 17 to the silicon substrate 12 throughheat-resistant glass, such as Pyrex glass (tradename) (not shown), canimprove the working efficiency of later steps in the production of theapparatus for fine pattern formation.

[0130] As with the support member 7 described above, this support member17 is preferably formed of a material having a coefficient of linearexpansion in the range of one-tenth of the coefficient of linearexpansion of the silicon substrate 12 to 10 times the coefficient oflinear expansion of the silicon substrate 12.

[0131] The ink passage 18 is connected to the opening 17 c of thesupport member 17, and the other end of the ink passage 18 is connectedto an ink supplying device 19. In the embodiment shown in the drawing,only one ink passage 18 in a pipe form is connected. In this case, aconstruction may also be adopted wherein a plurality of openings 17 care provided, the number of the openings being determined by taking intoconsideration, for example, the size of the apparatus 11 for finepattern formation and the evenness of ink flow pressure, and the inkpassage 18 is connected to each opening 17 c. The support member 17 andthe silicon substrate 12 may be fabricated so that the ink passage isprovided within the support member 17 and/or the silicon substrate 12.

[0132] The ink supplying device 19 is not particularly limited, and anyof a continuous supply pump, a constant rate supply pump and the likemay be used as the ink supplying device 19 and may be properly selectedaccording to the application of the apparatus 11 for fine patternformation.

[0133] In this apparatus 11 for fine pattern formation according to thepresent invention, ink can be ejected through the plurality of finenozzles 15 on the back surface of the silicon substrate 12 in a verysmall amount with high accuracy at substantially even ejection width,and, at the same time, the deposition of ink onto the back surface ofthe silicon substrate 12 can be prevented. The amount of ink ejected canbe set as desired by varying the amount of ink supplied through thecontrol of the ink supplying device 19. Therefore, a pattern can bestably formed by direct writing with high accuracy on a pattern object.Further, since the fine nozzles 15 have nozzle bases 15 a, the finenozzles 15 have high mechanical strength and are highly durable againstexternal impact and ink supply pressure.

Third Embodiment

[0134]FIG. 3 is a schematic cross-sectional view showing still anotherembodiment of the apparatus for fine pattern formation according to thepresent invention. As shown in FIG. 3, an apparatus 1′ for fine patternformation comprises a silicon substrate 2′, tapered concaves 3′aprovided on a surface 2′A of the silicon substrate 2′, fine nozzles 5protruded on the back surface 2′B side of the silicon substrate 2′, asilicon nitride layer 6 provided on the surface 2′A and a side face 2′Cof the silicon substrate 2′, a support member 7, an ink passage 8 forsupplying ink to a space between the silicon substrate 2′ and thesupport member 7, and an ink supplying device 9 connected to the inkpassage 8.

[0135] The silicon substrate 2′ has fine holes 3 which extend throughthe silicon substrate 2′ from the bottom of the plurality of taperedconcaves 3′a on the surface 2′A side to the back surface 2′B side.Openings 3 a on the surface 2′A side of the fine holes 3 are exposed tothe tapered concaves 3′a, and the tapered concaves 3′a are exposed tothe space defined by the silicon substrate 2′ and the support member 7.Preferably, the silicon substrate 2′ is formed of a single crystal ofsilicon, in which the crystallographic orientation of the surface 2′Aand the back surface 2′B is <100> face, and has a thickness of about 200to 500 μm. Since the silicon substrate 2′ has a low coefficient oflinear expansion of about 2.6×10⁻⁶/K, a change in shape upon atemperature change is very small.

[0136] A silicon oxide layer 4 is provided on the wall surface of thetapered concaves 3′a, and the thickness of the silicon oxide layer 4 isgenerally about 5000 to 10000 angstroms. The taper in the concaves 3′amay be in the form of any of an inverted cone, an inverted quadrangularpyramid and the like, and the depth of the concaves 3′a may be set inthe range of about 5 to 150 μm, and the maximum opening diameter may beset in the range of about 10 to 200 μm. For example, when the taper isin an inverted quadrangular pyramid form, the wall surface of theconcaves 3′a may be formed so that the angle of the wall surface of theconcaves 3′a to the surface 2′A of the silicon substrate 2′ (<100> face)is 55 degrees. In the embodiment shown in the drawing, the thickness ofthe silicon substrate 2′, the number of tapered concaves 3′a, the pitchof the tapered concaves 3′a and the like are simplified for theexplanation of the construction of the apparatus. The number of theconcaves 3′a and the pitch of the concaves 3′a, together with the fineholes 3, may be properly set according to the form of pattern formed bythe apparatus 1′ for fine pattern formation, the method for patternformation and the like. The pitch of the concaves 3′a is preferablyabout 15 μm at the smallest.

[0137] The fine holes 3 are cylindrical spaces which are circular in atransverse section perpendicular to the axial direction (a sectionparallel to the surface 2′A of the silicon substrate 2′) and arerectangular in a longitudinal section along the axial direction (asection perpendicular to the surface 2′A of the silicon substrate 2′). Asilicon oxide layer 4 is provided on the wall surface of the fine holes3 so as to be continued from the wall surface of the concaves 3′a. Inthe embodiment shown in the drawing, the inner diameter of the fineholes 3, the number of fine holes, the pitch of the fine holes and thelike are simplified for the explanation of the construction of theapparatus. The inner diameter of the fine holes 3 may be properly set inthe range of about 1 to 100 μm, and the aspect ratio of the fine holes 3may be properly set in the range of about 1 to 100. The number of thefine holes 3 and the pitch of the fine holes 3 may be properly setaccording to the form of a pattern formed by the apparatus 1′ for finepattern formation, the method for pattern formation and the like. Thepitch of the fine holes 3 is preferably about 15 μm at the smallest.

[0138] The transverse sectional form of the fine holes 3 may be, inaddition to the above-described circular form, for example, anelliptical or polygonal form or a special form. Further, the fine holes3 may be a combination of two or more fine holes which are differentfrom each other in transverse sectional form. When the fine holes areelliptical or rectangular in transverse sectional form, the innerdiameter in the longitudinal direction may be properly set in the rangeof 5 to 500 μm. The inner diameter of the fine holes 3 is substantiallyeven in the axial direction, and the variation in the inner diameter isgenerally within ±1 μm.

[0139] The fine nozzles 5 are formed of silicon oxide, are providedintegrally with the silicon oxide layer 4 provided on the wall surfaceof the fine holes 3, and are in communication with the fine holes 3. Thethickness of the fine nozzles 5 may be properly set in the range of 5000to 10000 angstroms, the opening diameter (inner diameter) may beproperly set in the range of 1 to 100 μm, and the protrusion level maybe properly set in the range of 1 to 150 μm. The opening diameter of theplurality of fine nozzles 5 is substantially even, and the variation inthe opening diameter is generally within ±1 μm. The provision of suchfine nozzles 5 can prevent ink, ejected from the fine holes 3, frombeing deposited on the back surface 2′B side of the silicon substrate2′.

[0140] The silicon nitride layer 6, the support member 7, the inkpassage 8, and the ink supplying device 9 are the same as thosedescribed above in connection with the apparatus 1 for fine patternformation, and the explanation thereof will be omitted.

[0141] In this apparatus 1′ for fine pattern formation according to thepresent invention, by virtue of the provision of tapered concaves 3′a,the passage resistance of ink can be reduced, and an ink having higherviscosity can be ejected through the plurality of fine nozzles 5 on theback surface of the silicon substrate 2′ in a very small amount withhigh accuracy at substantially even ejection width, and, at the sametime, the deposition of ink onto the back surface of the siliconsubstrate 2′ can be prevented. The amount of ink ejected can be set asdesired by varying the amount of ink supplied through the control of theink supplying device 9. Therefore, a pattern can be stably formed bydirect writing with high accuracy on a pattern object.

Fourth embodiment

[0142]FIG. 4 is a schematic cross-sectional view showing a furtherembodiment of the apparatus for fine pattern formation according to thepresent invention. As shown in FIG. 4, an apparatus 11′ for fine patternformation comprises a silicon substrate 12′, tapered concaves 13′aprovided on a surface 12′A of the silicon substrate 12′, fine nozzles 15protruded on the back surface 12′B side of the silicon substrate 12′, asupport member 17, an ink passage 18 for supplying ink to a spacebetween the silicon substrate 12′ and the support member 17, and an inksupplying device 19 connected to the ink passage 18.

[0143] The silicon substrate 12′ has fine holes 13 which extend throughthe silicon substrate 12′ from the bottom of the plurality of taperedconcaves 13′a on the surface 12′A side to the back surface 12′B side.Openings 13 a on the surface 12′A side of the fine holes 13 are exposedto the tapered concaves 13′a, and the tapered concaves 13′a are exposedto the space defined by the silicon substrate 12′ and the support member17. Preferably, the silicon substrate 12′ is formed of a single crystalof silicon, in which the crystallographic orientation of the surface12′A and the back surface 12′B is <100> face, and has a thickness ofabout 200 to 500 μm.

[0144] A silicon oxide layer 14 is provided on the wall surface of thetapered concaves 13′a, and the thickness of the silicon oxide layer 14is generally about 5000 to 10000 angstroms. The taper in the concaves13′a may be in the form of any of an inverted cone, an invertedquadrangular pyramid and the like, and the depth of the concaves 13′amay be set in the range of about 5 to 150 μm, and the maximum openingdiameter may be set in the range of about 10 to 200 μm. For example,when the taper is in an inverted quadrangular pyramid form, the wallsurface of the concaves 13′a may be formed so that the angle of the wallsurface of the concaves 13′a to the surface 12′A of the siliconsubstrate 12′ (<100> face) is 55 degrees. In the embodiment shown in thedrawing, the thickness of the silicon substrate 12′, the number oftapered concaves 13′a, the pitch of the tapered concaves 13′a and thelike are simplified for the explanation of the construction of theapparatus. The number of the concaves 13′a and the pitch of the concaves13′a, together with the fine holes 13, may be properly set according tothe form of pattern formed by the apparatus 11′ for fine patternformation, the method for pattern formation and the like. The pitch ofthe concaves 13′a is preferably about 15 μm at the smallest.

[0145] The fine holes 13 are cylindrical spaces which are circular in atransverse section perpendicular to the axial direction (a sectionparallel to the surface 12′A of the silicon substrate 12′) and arerectangular in a longitudinal section along the axial direction (asection perpendicular to the surface 12′A of the silicon substrate 12′).A silicon oxide layer 14 is provided on the wall surface of the fineholes 13 so as to be continued from the wall surface of the concaves13′a. In the embodiment shown in the drawing, the diameter of the fineholes 13, the number of fine holes 13, the pitch of the fine holes 13and the like are simplified for the explanation of the construction ofthe apparatus. The diameter of the fine holes 13 may be properly set inthe range of about 1 to 100 μm, and the aspect ratio of the fine holes13 may be properly set in the range of about 1 to 100. The number of thefine holes 13 and the pitch of the fine holes 13 may be properly setaccording to the form of pattern formed by the apparatus 11′ for finepattern formation, the method for pattern formation and the like. Thepitch of the fine holes 13 is preferably about 15 μm at the smallest.

[0146] The transverse sectional form of the fine holes 13 may be, inaddition to the above-described circular form, for example, anelliptical or polygonal form or a special form. Further, the fine holes13 may be a combination of two or more fine holes which are differentfrom each other in transverse sectional form. When the fine holes areelliptical or rectangular in transverse sectional form, the diameter inthe longitudinal direction may be properly set in the range of 5 to 500μm. The diameter of the fine holes 13 is substantially even in the axialdirection, and the variation in the diameter is generally within ±1 μm.

[0147] The fine nozzles 15 each comprise: a nozzle base 15 a providedintegrally with the silicon substrate 12′; an inner surface layer 15 bof silicon oxide provided on the inner wall surface of the nozzle base15 a in communication with the fine hole 13; and an end face layer 15 cof silicon oxide provided so as to cover the front end face of thenozzle base 15 a. The inner surface layer 15 b of silicon oxide and theend face layer 15 c of silicon oxide are provided integrally with thesilicon oxide layer 14 provided on the wall surface of the fine hole 13.The outer diameter of the nozzle bases 15 a may be properly set in therange of 3 to 150 μm, and the wall thickness of the nozzle bases 15 amay be properly set in the range of 1 to 25 μm. The thickness of theinner surface layer 15 b of silicon oxide and the thickness of the endface layer 15 c of silicon oxide may be properly set in the range of5000 to 10000 angstroms, the opening diameter of the fine nozzles 15(the inner diameter of the inner surface layer 15 b of silicon oxide)may be properly set in the range of 1 to 100 μm, and the protrusionlevel of the fine nozzles 15 (the height of the nozzle bases 15 a) maybe properly set in the range of 1 to 150 μm. The opening diameter of theplurality of fine nozzles 15 is substantially even, and the variation inthe opening diameter is generally within ±1 μm. The provision of suchfine nozzles 15 can prevent ink, ejected from the fine holes 13, frombeing deposited on the back surface 12′B side of the silicon substrate12′.

[0148] The support member 17, the ink passage 18, and the ink supplyingdevice 19 are the same as those described above in connection with theapparatus 11 for fine pattern formation, and the explanation thereofwill be omitted.

[0149] In this apparatus 11′ for fine pattern formation according to thepresent invention, by virtue of the provision of tapered concaves 13′a,the passage resistance of ink can be reduced, and an ink having higherviscosity can be ejected through the plurality of fine nozzles 15 on theback surface of the silicon substrate 12′ in a very small amount withhigh accuracy at substantially even ejection width, and, at the sametime, the deposition of ink onto the back surface of the siliconsubstrate 12′ can be prevented. The amount of ink ejected can be set asdesired by varying the amount of ink supplied through the control of theink supplying device 19. Therefore, a pattern can be stably formed bydirect writing with high accuracy on a pattern object. Further, sincethe fine nozzles 15 have nozzle bases 15 a, the fine nozzles 15 havehigh mechanical strength and are highly durable against external impactand ink supply pressure.

Fifth Embodiment

[0150]FIG. 5 is a schematic cross-sectional view showing a still furtherembodiment of the apparatus for fine pattern formation according to thepresent invention. As shown in FIG. 5, an apparatus 1″ for fine patternformation comprises a silicon substrate 2″, multistaged concaves 3″aprovided on a surface 2″A of the silicon substrate 2″, fine nozzles 5protruded on the back surface 2″B side of the silicon substrate 2″, asilicon nitride layer 6 provided on the surface 2″A and a side face 2″Cof the silicon substrate 2″, a support member 7, an ink passage 8 forsupplying ink to a space between the silicon substrate 2″ and thesupport member 7, and an ink supplying device 9 connected to the inkpassage 8.

[0151] The silicon substrate 2″ has fine holes 3 which extend throughthe silicon substrate 2″ from the bottom of the plurality of multistagedconcaves 3″a on the surface 2″A side to the back surface 2″B side.Openings 3 a on the surface 2″A side of the fine holes 3 are exposed tothe concaves 3″a, and the concaves 3″a are exposed to the space definedby the silicon substrate 2″ and the support member 7. According to thisconstruction, the fine holes 3 each have a two-staged concave openingcomprising the opening 3 a as a fine opening and the concave 3″a as awide opening.

[0152] The silicon substrate 2″ may be formed of the same material as inthe silicon substrate 2, and the thickness of the silicon substrate 2″also may be set in the same range as that of the silicon substrate 2.The silicon substrate 2″ may be an SOI (silicon on insulator) wafer thathas a thin film of silicon oxide, which is parallel to the surface ofthe substrate 2″, at the boundary between the concaves 3″a and the fineholes 3.

[0153] A silicon oxide layer 4 is provided on the wall surface of theconcaves 3″a, and the thickness of the silicon oxide layer 4 isgenerally about 5000 to 10000 angstroms. The concaves 3″a may be in acylindrical, cubic, rectangular parallelopiped or other form, and thedepth of the concaves 3″a may be set in the range of about 1 to 150 μm,and the opening diameter may be set in the range of about 5 to 200 μm.In the embodiment shown in the drawing, the thickness of the siliconsubstrate 2″, the number of concaves 3″a, the pitch of the concaves 3″aand the like are simplified for the explanation of the construction ofthe apparatus. The number of the concaves 3″a and the pitch of theconcaves 3″a, together with the fine holes 3, may be properly setaccording to the form of pattern formed by the apparatus 1″ for finepattern formation, the method for pattern formation and the like. Thepitch of the concaves 3″a is preferably about 10 μm at the smallest.Further, in the embodiment shown in the drawing, as described above,two-staged openings of the opening 3 a as the fine opening and theconcave 3″a as the wide opening are adopted. Alternatively, three- ormore staged openings may be adopted.

[0154] The fine holes 3 are cylindrical spaces which are circular in atransverse section perpendicular to the axial direction (a sectionparallel to the surface 2″A of the silicon substrate 2″) and arerectangular in a longitudinal section along the axial direction (asection perpendicular to the surface 2″A of the silicon substrate 2″). Asilicon oxide layer 4 is provided on the wall surface of the fine holes3 so as to be continued from the wall surface of the concaves 3″a. Inthe embodiment shown in the drawing, the inner diameter of the fineholes 3, the number of fine holes 3, the pitch of the fine holes 3 andthe like are simplified for the explanation of the construction of theapparatus. The inner diameter of the fine holes 3 may be properly set inthe range of about 1 to 100 μm, and the aspect ratio of the fine holes 3may be properly set in the range of about 1 to 100. The number of thefine holes 3 and the pitch of the fine holes 3 may be properly setaccording to the form of pattern formed by the apparatus 1″ for finepattern formation, the method for pattern formation and the like. Thepitch of the fine holes 3 is preferably about 10 μm at the smallest.

[0155] The transverse sectional form of the fine holes 3 may be, inaddition to the above-described circular form, for example, anelliptical or polygonal form or a special form. Further, the fine holes3 may be a combination of two or more fine holes which are differentfrom each other in transverse sectional form. When the fine holes areelliptical or rectangular in transverse sectional form, the innerdiameter in the longitudinal direction may be properly set in the rangeof 5 to 500 μm. The inner diameter of the fine holes 3 is substantiallyeven in the axial direction, and the variation in the inner diameter isgenerally within ±1 μm.

[0156] The fine nozzles 5 are formed of silicon oxide, are providedintegrally with the silicon oxide layer 4 provided on the wall surfaceof the fine holes 3, and are in communication with the fine holes 3. Thethickness of the fine nozzles 5 may be properly set in the range of 5000to 10000 angstroms, the opening diameter (inner diameter) may beproperly set in the range of 1 to 100 μm, and the protrusion level maybe properly set in the range of 1 to 150 μm. The opening diameter of theplurality of fine nozzles 5 is substantially even, and the variation inthe opening diameter is generally within ±1 μm. The provision of suchfine nozzles 5 can prevent ink, ejected from the fine holes 3, frombeing deposited on the back surface 2″B side of the silicon substrate2″.

[0157] The silicon nitride layer 6, the support member 7, the inkpassage 8, and the ink supplying device 9 are the same as thosedescribed above in connection with the apparatus 1 for fine patternformation, and the explanation thereof will be omitted.

[0158] In this apparatus 1″ for fine pattern formation according to thepresent invention, by virtue of the provision of multistaged concaves3″a, the passage resistance of ink can be reduced, and an ink havinghigher viscosity can be ejected through the plurality of fine nozzles 5on the back surface of the silicon substrate 2″ in a very small amountwith high accuracy at substantially even ejection width, and, at thesame time, the deposition of ink onto the back surface of the siliconsubstrate 2″ can be prevented. The amount of ink ejected can be set asdesired by varying the amount of ink supplied through the control of theink supplying device 9. Therefore, a pattern can be stably formed bydirect writing with high accuracy on a pattern object.

Sixth Embodiment

[0159]FIG. 6 is a schematic cross-sectional view showing anotherembodiment of the apparatus for fine pattern formation according to thepresent invention. As shown in FIG. 6, an apparatus 11″ for fine patternformation comprises a silicon substrate 12″, multistaged concaves 13″aprovided on a surface 12″A of the silicon substrate 12″, fine nozzles 15protruded on the back surface 12″B side of the silicon substrate 12″, asupport member 17, an ink passage 18 for supplying ink to a spacebetween the silicon substrate 12″ and the support member 17, and an inksupplying device 19 connected to the ink passage 18.

[0160] The silicon substrate 12″ has fine holes 13 which extend throughthe silicon substrate 12″ from the bottom of the plurality ofmultistaged concaves 13″a on the surface 12″A side to the back surface12″B side. Openings 13 a on the surface 12″A side of the fine holes 13are exposed within the concaves 13″a, and the concaves 13″a are exposedto the space defined by the silicon substrate 12″ and the support member17. According to this construction, the fine holes 13 each have atwo-staged opening comprising the opening 13 a as a fine opening and theconcave 13″a as a wide opening.

[0161] The silicon substrate 12″ may be formed of the same material asin the silicon substrate 2, and the thickness of the silicon substrate12″ also may be set in the same range as that of the silicon substrate2. The silicon substrate 12″ may be an SOI (silicon on insulator) waferthat has a thin film of silicon oxide, which is parallel to the surfaceof the substrate 12″, at the boundary between the concaves 13″a and thefine holes 13.

[0162] A silicon oxide layer 14 is provided on the wall surface of theconcaves 13″a, and the thickness of the silicon oxide layer 14 isgenerally about 5000 to 10000 angstroms. The concaves 13″a may be in acylindrical, cubic, rectangular parallelopiped or other form, and thedepth of the concaves 13″a may be set in the range of about 1 to 150 μm,and the opening diameter may be set in the range of about 5 to 200 μm.In the embodiment shown in the drawing, the thickness of the siliconsubstrate 12″, the number of concaves 13″a, the pitch of the concaves13″a and the like are simplified for the explanation of the constructionof the apparatus. The number of the concaves 13″a and the pitch of theconcaves 13″a, together with the fine holes 13, may be properly setaccording to the form of pattern formed by the apparatus 11″ for finepattern formation, the method for pattern formation and the like. Thepitch of the concaves 13″a is preferably about 10 μm at the smallest.Further, in the embodiment shown in the drawing, as described above,two-staged openings of the opening 13 a as the fine opening and theconcave 13″a as the wide opening are adopted. Alternatively, three- ormore staged openings may be adopted.

[0163] The fine holes 13 are cylindrical spaces which are circular in atransverse section perpendicular to the axial direction (a sectionparallel to the surface 12″A of the silicon substrate 12″) and arerectangular in a longitudinal section along the axial direction (asection perpendicular to the surface 12″A of the silicon substrate 12″).A silicon oxide layer 14 is provided on the wall surface of the fineholes 13 so as to be continued from the wall surface of the concaves13″a. In the embodiment shown in the drawing, the diameter of the fineholes 13, the number of fine holes 13, the pitch of the fine holes 13and the like are simplified for the explanation of the construction ofthe apparatus. The diameter of the fine holes 13 may be properly set inthe range of about 1 to 100 μm, and the aspect ratio of the fine holes13 may be properly set in the range of about 1 to 100. The number of thefine holes 13 and the pitch of the fine holes 13 may be properly setaccording to the form of pattern formed by the apparatus 11″ for finepattern formation, the method for pattern formation and the like. Thepitch of the fine holes 13 is preferably about 10 μm at the smallest.

[0164] The transverse sectional form of the fine holes 13 may be, inaddition to the above-described circular form, for example, anelliptical or polygonal form or a special form. Further, the fine holes13 may be a combination of two or more fine holes which are differentfrom each other in transverse sectional form. When the fine holes areelliptical or rectangular in transverse sectional form, the diameter inthe longitudinal direction may be properly set in the range of 5 to 500μm. The diameter of the fine holes 13 is substantially even in the axialdirection, and the variation in the diameter is generally within ±1 μm.

[0165] The fine nozzles 15 each comprise: a nozzle base 15 a providedintegrally with the silicon substrate 12″; an inner surface layer 15 bof silicon oxide provided on the inner wall surface of the nozzle base15 a in communication with the fine hole 13; and an end face layer 15 cof silicon oxide provided so as to cover the front end face of thenozzle base 15 a. The inner surface layer 15 b of silicon oxide and theend face layer 15 c of silicon oxide are provided integrally with thesilicon oxide layer 14 provided on the wall surface of the fine hole 13.The outer diameter of the nozzle bases 15 a may be properly set in therange of 3 to 150 μtm, and the wall thickness of the nozzle bases 15 amay be properly set in the range of 1 to 25 μm. The thickness of theinner surface layer 15 b of silicon oxide and the thickness of the endface layer 15 c of silicon oxide may be properly set in the range of5000 to 10000 angstroms, the opening diameter of the fine nozzles 15(the inner diameter of the inner surface layer 15 b of silicon oxide)may be properly set in the range of 1 to 100 μm, and the protrusionlevel of the fine nozzles 15 (the height of the nozzle bases 15 a) maybe properly set in the range of 1 to 150 μm. The opening diameter of theplurality of fine nozzles 15 is substantially even, and the variation inthe opening diameter is generally within ±1 μm. The provision of suchfine nozzles 15 can prevent ink, ejected from the fine holes 13, frombeing deposited on the back surface 12″B side of the silicon substrate12″.

[0166] The support member 17, the ink passage 18, and the ink supplyingdevice 19 are the same as those described above in connection with theapparatus 11 for fine pattern formation, and the explanation thereofwill be omitted.

[0167] In this apparatus 11″ for fine pattern formation according to thepresent invention, by virtue of the provision of multistaged concaves13″a, the passage resistance of ink can be reduced, and an ink havinghigher viscosity can be ejected through the plurality of fine nozzles 15on the back surface of the silicon substrate 12″ in a very small amountwith high accuracy at substantially even ejection width, and, at thesame time, the deposition of ink onto the back surface of the siliconsubstrate 12″ can be prevented. The amount of ink ejected can be set asdesired by varying the amount of ink supplied through the control of theink supplying device 19. Therefore, a pattern can be stably formed bydirect writing with high accuracy on a pattern object. Further, sincethe fine nozzles 15 have nozzle bases 15 a, the fine nozzles 15 havehigh mechanical strength and are highly durable against external impactand ink supply pressure.

Seventh Embodiment

[0168]FIG. 7 is a schematic cross-sectional view showing still anotherembodiment of the apparatus for fine pattern formation according to thepresent invention, and FIG. 8 is a bottom view of an apparatus for finepattern formation shown in FIG. 7. In FIGS. 7 and 8, the apparatus 21for fine pattern formation comprises three continuous apparatus units 21a, 21 b, 21 c, that is, comprises a common silicon substrate 22, aplurality of fine nozzles 25 protruded from the back surface of thesilicon substrate 22, three support members 27 provide on the surface22A side of the silicon substrate 22, three ink passages 28 forsupplying ink to spaces between the silicon substrate 22 and each of thesupport members 27, and ink supplying devices 29 a, 29 b, 29 c connectedto these respective ink passages 28.

[0169] For each of the apparatus units 21 a, 21 b, 21 c, the siliconsubstrate 22 has a plurality of fine holes 23 extending through thesilicon substrate 22 from the surface 22A side of the silicon substrate22 to the back surface 22B side of the silicon substrate 22, and theopenings 23 a on the surface 22A side of the fine holes 23 are exposedto the spaces defined by the silicon substrate 22 and the supportmembers 27. The silicon substrate 22 may be formed of the same materialas the above-described silicon substrate 2, and the thickness of thesilicon substrate 22 also may be set in the same range as in the siliconsubstrate 2.

[0170] For each of the apparatus units 21 a, 21 b, 21 c, the fine holes23 are provided in a pattern such that a plurality of fine holes arearranged along a predetermined direction (in a direction indicated by anarrow A in FIG. 8) in an identical line. Openings 25 d in the finenozzles 25, which will be described later, are also arranged in the samemanner as adopted in the fine holes 23. Specifically, in the apparatusunit 21 a, a plurality of lines of fine holes 23 arranged along thedirection indicated by the arrow A are provided at pitch P1. Likewise,also in the apparatus unit 21 b, the apparatus unit 21 c, a plurality oflines of fine holes 23 are provided at pitch P1. The lines of the fineholes 23 in the apparatus units 21 a, the lines of the fine holes 23 inthe apparatus units 21 b, and the lines of the fine holes 23 in theapparatus units 21 c are deviated from one another at pitch P2(P1=3×P2). Therefore, in the whole apparatus 21 for fine patternformation, lines of fine holes in the apparatus units 21 a, 21 b, 21 care repeatedly arranged at pitch P2. The transverse sectional form, thelongitudinal sectional form, the inner diameter, and the pitch of thefine holes 23 may be properly set in the same manner as in the fineholes 13. The silicon oxide layer 24 provided on the wall surface of thefine holes 23 may also be the same as the silicon oxide layer 14. In theembodiment shown in the drawing, for example, the inner diameter, thenumber, and the pitch of the fine holes 23 provided with the siliconoxide layer 24 have been simplified for facilitating the explanation ofthe construction of the apparatus.

[0171] The fine nozzles 25 have the same construction as the finenozzles 15 and each comprise: a nozzle base 25 a provided integrallywith the silicon substrate 22; an inner surface layer 25 b of siliconoxide provided on the inner wall surface of the nozzle base 25 a incommunication with the fine hole 23; and an end face layer 25 c ofsilicon oxide provided so as to cover the front end face of the nozzlebase 25 a. The inner surface layer 25 b of silicon oxide and the endface layer 25 c of silicon oxide are provided integrally with thesilicon oxide layer 24 provided on the wall surface of the fine hole 23.In this fine nozzles 25, the outer diameter and wall thickness of thenozzle bases 25 a, the thickness of the inner surface layer 25 b ofsilicon oxide and the end face layer 25 c of silicon oxide, the innerdiameter of the openings 25 d in the fine nozzles 25 (the inner diameterof the inner surface layer 25 b of silicon oxide), and the protrusionlevel of the fine nozzles 25 (the height of the nozzle bases 25 a) maybe set in the same respective ranges as described above in connectionwith the fine nozzles 15. The opening diameter of the plurality of finenozzles 25 is substantially even, and the variation in the openingdiameter is generally within ±1 μm. The provision of such fine nozzles25 can prevent ink, ejected from the fine holes 23, from being depositedon the back surface 22B side of the silicon substrate 22.

[0172] The support member 27 is provided on the surface 22A side of thesilicon substrate 22, for supporting the silicon substrate 22. In theembodiment shown in the drawing, as with the support member 7 describedabove, the support member 27 comprises: a base 27 a, which, as with thesilicon substrate 22, is flat; a flange portion 27 b provided on theperiphery of the base 27 a; and an opening 27 c provided at the centerof the base 27 a. The support member 27 is fixed to the surface 22A sideof the silicon substrate 22 by the flange portion 27 b. This can providea space for supplying ink to a portion between the silicon substrate 22and the support member 27. The fixation of the support member 27 to thesilicon substrate 22 through heat-resistant glass, such as Pyrex glass(tradename) (not shown), can improve the working efficiency of latersteps in the production of the apparatus for fine pattern formation. Aswith the support member 7 described above, this support member 27 ispreferably formed of a material having a coefficient of linear expansionin the range of one-tenth of the coefficient of linear expansion of thesilicon substrate 22 to 10 times the coefficient of linear expansion ofthe silicon substrate 22.

[0173] The ink passages 28 are connected to the openings 27 c of therespective support members 27, and the other ends of the ink passages 28are connected respectively to ink supplying devices 29 a, 29 b, 29 c.The ink supplying devices 29 a, 29 b, 29 c may be properly selected froma continuous supply pump, a constant rate supply pump and the likeaccording to applications of the apparatus 11 for fine patternformation. In the embodiment shown in the drawing, only one ink passage28 is provided in each support member 27. In this case, a constructionmay also be adopted wherein a plurality of openings 27 c, the number ofwhich is determined by taking into consideration, for example, theevenness of ink flow pressure, are provided for one support member 27,and the ink passage 28 is connected to each opening 27 c. The inkpassage may be provided within the support member 27.

[0174] In this apparatus 21 for fine pattern formation according to thepresent invention, ink can be ejected through the plurality of finenozzles 25 on the back surface of the silicon substrate 22 in a verysmall amount with high accuracy at substantially even ejection width,and, at the same time, the deposition of ink onto the back surface ofthe silicon substrate 22 can be prevented. Different inks may besupplied respectively from the ink supplying devices 29 a, 29 b, 29 c todirectly write a pattern with a desired ink for each of the apparatusunits 21 a, 21 b, 21 c. Further, the amount of ink ejected may be set asdesired by regulating the ink supplying devices 29 a, 29 b, 29 c to varythe amount of ink supplied. Furthermore, in the apparatus 21 for finepattern formation, since the apparatus units 21 a, 21 b, 21 c areprovided integrally with one another, there is no need to join aplurality of apparatuses to one another and, in addition, the positionalaccuracy of the apparatuses is very high. Furthermore, since the finenozzles 25 have nozzle bases 25 a, the fine nozzles 25 have highmechanical strength and are highly durable against external impact andink supply pressure.

[0175] In the apparatus 21 for fine pattern formation, the fine nozzles5 as shown in FIG. 1 may be provided on the back surface 22B side of thesilicon substrate 22.

[0176] Also in the apparatus 21 for fine pattern formation, the openings23 a on the surface 22A side of the fine holes 23 may be in a taperedconcave form or a multistaged concave form as described above. This canreduce passage resistance and can realize the ejection of a very smallamount of a higher-viscosity ink through the plurality of fine nozzles25 at substantially even ejection width with high accuracy.

Eighth Embodiment

[0177]FIG. 9 is a diagram showing a further embodiment of the apparatusfor fine pattern formation according to the present invention, whereinFIG. 9 (A) is a schematic cross-sectional view and FIG. 9 (B) a bottomview. In FIG. 9, an apparatus 31 for fine pattern formation comprises: asilicon substrate 32; a plurality of fine nozzles 35 protruded from theback surface 32B of the silicon substrate 32; a support member 37provided on the surface 32A side of the silicon substrate 32; three inkpassages 38 a, 38 b, 38 c provided within the silicon substrate 32 andwithin the support member 37; and ink supplying devices 39 a, 39 b, 39 cconnected respectively to the ink passages.

[0178] The silicon substrate 32 is provided with a plurality of fineholes 33 which extend through the silicon substrate 32 from the surface32A side of the silicon substrate 32 to the back surface 32B side of thesilicon substrate 32, and openings 33 a on the surface 32A side of thefine holes 33 each are exposed within any one of the three ink passages38 a, 38 b, 38 c provided in a groove form on the surface 32A side. Thesilicon substrate 32 may be formed of the same material as the siliconsubstrate 2, and the thickness of the silicon substrate 32 may also beset in the same range as the silicon substrate 2.

[0179] A plurality of fine holes 33 (openings 35 d in fine nozzles 35described later) are arranged on an identical line along a predetermineddirection (direction indicated by an arrow a in FIG. 9 (B)). A pluralityof these lines are provided at pitch P. In the embodiment shown in thedrawing, six fine hole lines 33A, 33B, 33C, 33D, 33E, 33F, in each ofwhich a plurality of fine holes are arranged along a direction indicatedby the arrow a, are provided at pitch P. The transverse sectional form,the longitudinal sectional form, the inner diameter, and the pitch ofthe fine holes 33 may be properly set in the same manner as in the fineholes 3.The silicon oxide layer 34 provided on the wall surface of thefine holes 33 may also be the same as the silicon oxide layer 14. In theembodiment shown in the drawing, for example, the inner diameter, thenumber, and the pitch of the fine holes 33 provided with the siliconoxide layer 34 have been simplified for facilitating the explanation ofthe construction of the apparatus.

[0180] The fine nozzles 35 have the same construction as the finenozzles 15 and each comprise: a nozzle base 35 a provided integrallywith the silicon substrate 32; an inner surface layer 35 b of siliconoxide provided on the inner wall surface of the nozzle base 35 a incommunication with the fine hole 33; and an end face layer 35 c ofsilicon oxide provided so as to cover the front end face of the nozzlebase 35 a. The inner surface layer 35 b of silicon oxide and the endface layer 35 c of silicon oxide are provided integrally with thesilicon oxide layer 34 provided on the wall surface of the fine hole 33.In this fine nozzles 35, the outer diameter and wall thickness of thenozzle bases 35 a, the thickness of the inner surface layer 35 b ofsilicon oxide and the end face layer 35 c of silicon oxide, the innerdiameter of the openings 35 d in the fine nozzles 35 (the inner diameterof the inner surface layer 35 b of silicon oxide), and the protrusionlevel of the fine nozzles 35 (the height of the nozzle bases 35 a) maybe set in the same respective ranges as described above in connectionwith the fine nozzles 15. The opening diameter of the plurality of finenozzles 35 is substantially even, and the variation in the openingdiameter is generally within ±1 μm. The provision of such fine nozzles35 can prevent ink, ejected from the fine holes 33, from being depositedon the back surface 32B side of the silicon substrate 32.

[0181] The support member 37 is a plate member which is provided on thesurface 32A side of the silicon substrate 32 to hold the siliconsubstrate 32, and ink passages 38 c are provided in a groove form in thesupport member 37 on its silicon substrate 32 side.

[0182]FIG. 10 is a transverse sectional view taken on line A-A of thesilicon substrate 32 shown in FIG. 9 (A), and FIG. 11 a transversesectional view taken on line B-B of the support member 37 shown in FIG.9 (A).

[0183] As shown in FIG. 9 (A) and FIG. 10, in the silicon substrate 32,an ink passage 38 a in a groove form is provided so as to connect eachof openings in fine hole lines 33A, 33D to the ink supplying device 39a, and an ink passage 38 b in a groove form is provided so as to connecteach of the openings in fine hole lines 33B, 33E to the ink supplyingdevice 39 b. Further, an ink passage 38 c in a groove form is providedon each of the openings in fine hole lines 33C, 33F. Further, as shownin FIG. 9 (A) and FIG. 11, in the support member 37, the ink passage 38c in a groove form is provided so as to connect each of the openings inthe fine hole lines 33C, 33F to the ink supplying device 39 c.

[0184] As shown in FIG. 12, three ink passages 38 a, 38 b, 38 c providedbetween the support member 37 and the silicon substrate 32 areindependent of one another. As with the support member 7, the supportmember 37 is preferably formed of a material having a coefficient oflinear expansion in the range of one-tenth of the coefficient of linearexpansion of the silicon substrate 32 to 10 times the coefficient oflinear expansion of the silicon substrate 32.

[0185] The ends of the ink passages 38 a, 38 b, 38 c are connectedrespectively to the ink supplying devices 39 a, 39 b, 39 c. The inksupplying devices 39 a, 39 b, 39 c are not particularly limited, and anyof a continuous supply pump, a constant rate supply pump and the likemay be used as the ink supplying device and may be properly selectedaccording to the application of the apparatus 31 for fine patternformation.

[0186] The apparatus 31 for fine pattern formation according to thepresent invention can eject ink through the plurality of fine nozzles 35provided on the back surface of the silicon substrate 32 in asubstantially even ejection width in a very small amount with highaccuracy and, at the same time, can prevent the deposition of ink ontothe back surface of the silicon substrate 32. The supply of differentinks respectively from the ink supplying devices 39 a, 39 b, 39 cpermits a pattern to be formed by direct writing with a desired ink foreach fine hole line grouped according to the ink passages 38 a, 38 b, 38c (a group consisting of fine hole lines 33A and 33D, a group consistingof fine hole lines 33B and 33E, and a group consisting of fine holelines 33C and 33F), and is particularly advantageous for the formationof a stripe pattern which will be described later. Further, since theapparatus 31 for fine pattern formation does not comprise a plurality ofmutually connected apparatus units for respective inks, the positionalaccuracy of each fine hole line is very high. Further, the amount of inkejected can be set as desired by regulating the ink supplying devices 39a, 39 b, 39 c to vary the amount of ink supplied. Further, since thefine nozzles 35 have nozzle bases 35 a, the fine nozzles 35 have highmechanical strength and are highly durable against external impact andink supply pressure.

[0187] In the apparatus 31 for fine pattern formation, fine nozzles 5 asshown in FIG. 1 may be provided on the back surface 32B side of thesilicon substrate 32.

[0188] Also in the apparatus 31 for fine pattern formation, the openingson the ink passage side of the fine holes 33 may be the above-describedtapered or multistaged concaves. This construction can reduce passageresistance and thus eject an ink having higher viscosity through theplurality of fine nozzles 35 in a substantially even ejection width in avery small amount with high accuracy.

Ninth Embodiment

[0189]FIG. 13 is a plan view showing a further embodiment of theapparatus for fine pattern formation according to the present invention.In FIG. 13, an apparatus 41 for fine pattern formation comprises asilicon substrate 42, a plurality of fine nozzles protruded from theback surface of the silicon substrate 42, an ink passage for supplyingink to a space between the silicon substrate 42 and the support member,and an ink supplying device connected to the ink passage. In FIG. 13,however, only the silicon substrate 42 is shown, and the fine nozzles,the support member, the ink passage, and the ink supplying device arenot shown.

[0190] The silicon substrate 42 has a plurality of fine holes 43 whichextend through the silicon substrate 42 from the surface 42A side of thesilicon substrate 42 to the back surface side of the silicon substrate42. The fine holes 43 are provided at positions such that the fine holes43 constitute one pattern 46, and a plurality of patterns 46 (10patterns in the embodiment shown in the drawing) are provided on thesilicon substrate 42. In the drawing, the fine holes 43 are shown inonly one pattern 46, and, for the other patterns 46, only the outline isindicated by a chain line.

[0191] The silicon substrate 42 may be formed of the same material asused in the silicon substrate 2, and the thickness of the siliconsubstrate 42 also may be set in the same range as in the siliconsubstrate 2. The transverse sectional form, the longitudinal sectionalform, the inner diameter, and the pitch of the fine holes 43 may beproperly set in the same manner as in the fine holes 3. The fine holes43 have a silicon oxide layer on their wall surface, and this siliconoxide layer also may be the same as the silicon oxide layer 4.

[0192] A plurality of fine nozzles are protruded on the back surface 42Bside of the silicon substrate 42 so as to communicate with the fineholes 43. The fine nozzles may be the same as the fine nozzles 5 or thefine nozzles 15.

[0193] Further, in the silicon substrate 42, a support member having, onits periphery, a flange portion as described above in connection withthe support member 7 may be provided, and the flange portion in thesupport member may be fixed to the peripheral portion (a shaded regionin FIG. 13). The ink supply passage may be connected to the opening ofthe support member, and the ink supplying device may be connected to theother end of the ink supply passage.

[0194] The apparatus 41 for fine pattern formation can eject ink throughthe fine holes 43 (fine nozzles) of the silicon substrate 42 in asubstantially even ejection width in a very small amount with highaccuracy. A pattern in a form corresponding to the pattern 46 can bestably formed on a pattern object with high accuracy by ejecting inkfrom the fine nozzles in the silicon substrate 42 in a suitable amountsuch that inks ejected from mutually adjacent fine nozzles come intocontact with each other on the pattern object. The amount of the inkejected can be regulated by controlling the ink supplying device.

[0195] In the above embodiment, all the plurality of patterns 46 are inan identical form. However, the present invention is not limited to thisonly. For example, the pattern may be in a desired form, such as aconductor pattern for a printed wiring board.

[0196] Also in the apparatus 41 for fine pattern formation, the openingsof the fine holes 43 may be the above-described tapered or multistagedconcaves. This can reduce the passage resistance, and an ink havinghigher viscosity can be ejected through the plurality of fine nozzles ina substantially even ejection width in a very small amount with highaccuracy.

[0197] The above-described apparatus for fine pattern formationaccording to the present invention can be applied, for example, to theformation of a black matrix pattern or a color pattern for liquidcrystal displays, the formation of a phosphor layer for plasma displays,and the formation of a pattern in electroluminescence, as well as toconductor pattern formation and correction of conductor patterns ofprinted wiring boards.

I-2 Formation of Fine Pattern

[0198] Next, the formation of a fine pattern using the apparatus forfine pattern formation according to the present invention will bedescribed.

[0199]FIG. 14 is a diagram illustrating one embodiment of fine patternformation using the apparatus 21 for fine pattern formation according tothe present invention. In FIG. 14, while supplying ink A, ink B, and inkC respectively from the ink supplying devices 29 a, 29 b, 29 c in theapparatus 21 for fine pattern formation according to the presentinvention through the ink passages 28, a pattern object S is scannedrelative to the apparatus 21 for fine pattern formation in apredetermined direction (a direction indicated by an arrow A). Thescanning direction A is identical to the arrangement direction A (seeFIG. 8) of the fine holes in the apparatus 21 for fine patternformation. In this case, the space between the silicon substrate 22 inthe apparatus 21 for fine pattern formation and the pattern object S maybe set in the range of about 0.1 to 5 mm.

[0200] According to this construction, inks ejected from the finenozzles 25 in the silicon substrate 22 form, by direct writing, a stripepattern comprising ink A, ink B, and ink C which have been repeatedlysequenced in that order on the pattern object S. In this case, the pitchof the stripes is P2. In this stripe pattern, since one stripe is formedof ink ejected from the plurality of fine nozzles on an identical line,even when the amount of ink ejected from the individual fine nozzles issmall, the scanning speed of the pattern object S can be increased toincrease the pattern formation speed. This stripe pattern is formed withvery high accuracy by varying the diameter of the fine holes 23 or thefine nozzles 25 to control the ejection width of ink, and the process issimpler than the conventional photolithography.

[0201] When the pattern object S is flexible, preferably, a back-uproller is disposed on the back surface of the pattern object S so as toface the apparatus 21 for fine pattern formation. In this case, thepattern object S is carried while applying tension to the pattern objectS by the back-up roller to directly write a pattern on the patternobject S.

[0202] Next, FIG. 15 is a diagram showing one embodiment of fine patternformation using the apparatus 41 for fine pattern formation according tothe present invention. In FIG. 15, the apparatus 41 for fine patternformation (only the silicon substrate 42 is shown in the embodiment inthe drawing) is disposed at a predetermined position of the patternobject S, a given amount of ink supplied from the ink passage is ejectedthrough the fine holes 43 (fine nozzles) onto the pattern object to forma pattern.

[0203] Thereafter, the pattern object S is carried by a predetermineddistance in a direction indicated by an arrow A, and the same patternformation as described above is carried out. A desired pattern 46 can beformed on the pattern object S by repeating the above procedure. Thespace between the silicon substrate 42 in the apparatus 41 for finepattern formation and the pattern object S may be set in the range ofabout 0.1 to 5 mm.

[0204] Further, a printed wiring board can be simply produced withoutreplying on photolithography, for example, by forming the pattern 46,formed of the plurality of fine holes 43 (fine nozzles) in the apparatus41 for fine pattern formation, as a conductor pattern of a printedwiring board, and using a conductor paste as ink.

I-3 Production Process of Fine Nozzles

[0205] Next, the production process of fine nozzles according to thepresent invention will be described.

First Embodiment

[0206] The production process of fine nozzles according to the presentinvention will be described by taking the fine nozzles 5 in theapparatus 1 for fine pattern formation shown in FIG. 1 as an examplewith reference to FIG. 16.

[0207] As the first step, an about 200 to 3000 angstrom-thick siliconnitride (Si₃N₄) layer 51 is formed on the whole area of the siliconsubstrate 2 having a cleaned surface (FIG. 16 (A)). The formation of thesilicon nitride layer 51 may be carried out, for example, by lowpressure CVD.

[0208] Next, a thin film as a mask is formed on the silicon nitridelayer 51 in its portion located on one surface of the silicon substrate.A photosensitive resist is coated on the thin film as the mask, andexposure through a predetermined photomask and development are carriedout to form a resist pattern. Subsequently, the mask thin film is etchedusing the resist pattern as a mask. Thereafter, the resist pattern isremoved to form a mask pattern 52 having fine openings (FIG. 16(B)). Thediameter of openings in fine holes 3 and fine nozzles 5, which will bedescribed later, is determined by the size of the fine openings in themask pattern 52. In general, the size of the fine openings is preferablyset in the range of 1 to 100 μm.

[0209] In addition to a metallic thin film, a resist, a thin film ofsilicon oxide or a combination of both the materials (resist/thin filmof silicon oxide) may be used as the mask thin film. Metallic thin filmsinclude thin films of aluminum, nickel, chromium and the like, and,preferably, the metallic thin film is formed to a thickness of about1000 to 2000 angstroms, for example, by sputtering or vacuum vapordeposition. For example, when aluminum is used as the metallic thinfilm, an aluminum etchant (mixed acid aluminum) may be used in theetching. Further, when the resist is formed as the mask thin film, spincoating may be used. In the case of silicon oxide, the thin film can beformed by sputtering or low pressure CVD.

[0210] Next, as the second step, through fine holes 3 are formed in thesilicon substrate 2 by a high aspect etching technique, such as deepetching, using the mask pattern 52 as a mask, (FIG. 16 (C)). Theformation of the through fine holes 3 may be carried out, for example,by a high aspect etching technique, such as a Bosch process using anICP-RIE (inductive coupled plasma-reactive ion etching) device.According to the present invention, since there is no need to regulatethe depth of the fine holes 3, the process is simple. This means that avariation in depth of the fine holes derived from a difference inetching rate in a singe wafer or between wafers does not substantiallyoccur. Therefore, the present invention is useful for an improvement inyield and for the production of an apparatus for writing a pattern on alarge area. Further, in particular, dry etching by ICP-RIE cansignificantly shorten the time necessary for the formation of thethrough fine holes 3.

[0211] Next, as the third step, the mask pattern 52 is removed, andoxidation is carried out in a thermal oxidation furnace to form an about5000 to 10000 angstrom-thick silicon oxide layer 4 on the wall surfaceof the through fine holes 3 (FIG. 16 (D)).

[0212] Next, as the fourth step, dry etching is carried out from onesurface of the silicon substrate 2. In this dry etching, after theremoval of the silicon nitride layer 51, a part of the silicon substrate2 is etched to expose the silicon oxide layer 4 formed on the inner wallof the through fine holes 3. When this silicon oxide layer 4 has beenexposed by a desired length, the dry etching is stopped to prepare finenozzles 5 formed of silicon oxide protruded on the etching side of thesilicon substrate 2.

[0213] Although the Bosch process utilizing an ICP-RIE device has beenused in the above high aspect etching, the present invention is notlimited to this only.

[0214] In the dry etching in the fourth step, preferably, only thesurface of the silicon substrate 2, on which the mask pattern 52 hasbeen formed, is selectively etched. The reason for this is as follows.Although the deep etching in the second step is likely to cause somevariation in shape of the etching end (lower side in the drawing), theaccuracy of etching of the silicon substrate on its surface side, wherethe mask pattern 52 has been formed, is very high. When this site isused as the front end side of the fine nozzles 5, a plurality of finenozzles 5 having an even opening diameter can be more easily prepared.

Second Embodiment

[0215] The production process of fine nozzles according to the presentinvention will be described by taking the fine nozzles 15 in theapparatus 11 for fine pattern formation shown in FIG. 2 as an examplewith reference to FIGS. 17 and 18.

[0216] As the first step, an about 200 to 3000 angstrom-thick siliconnitride (Si₃N₄) layer 61 is formed on the whole area of the siliconsubstrate 12 having a cleaned surface. A photosensitive resist is thencoated on the silicon nitride layer 61, and exposure through apredetermined photomask and development are carried out to form a resistpattern. Subsequently, the silicon nitride layer 61 is etched by RIE(reactive ion etching (process gas: CF₄ or SF₆)) using the resistpattern as a mask. Thereafter, the resist pattern is removed to form apattern having small openings 61 a (FIG. 17 (A)). The silicon nitridelayer 61 may be formed in the same manner as used in the formation ofthe silicon nitride layer 51. The size (outer diameter) of nozzle bases,which will be described later, is determined by the size of the smallopenings 61 a. In general, the opening diameter may be set in the rangeof 3 to 120 μm.

[0217] Next, as the second step, a mask thin film is formed on thepattern of the silicon nitride layer 61, a photosensitive resist iscoated on the mask thin film, and exposure through a predeterminedphotomask and development are carried out to form a resist pattern.Subsequently, the mask thin film is etched using the resist pattern as amask. Thereafter, the resist pattern is removed to form a mask pattern62 having fine openings 62 a (FIG. 17 (B)). The fine opening 62 a islocated within the small opening 61 a of the pattern of the siliconnitride layer 61, preferably in the center portion of the small opening61 a. The size of fine holes 13 and fine nozzles, which will bedescribed later, is determined by the size of the fine openings 62 a. Ingeneral, the opening diameter may be set in the range of 1 to 100 μm.

[0218] In addition to a metallic thin film, a resist, a thin film ofsilicon oxide or a combination of both the materials (resist/thin filmof silicon oxide) may be used as the mask thin film. Metallic thin filmsinclude thin films of aluminum, nickel, chromium and the like, and,preferably, the metallic thin film is formed to a thickness of about1000 to 2000 angstroms, for example, by sputtering or vacuum vapordeposition. For example, when aluminum is used as the metallic thinfilm, an aluminum etchant (mixed acid aluminum) may be used in theetching. Further, when the resist is formed as the mask thin film, spincoating may be used. In the case of silicon oxide, the thin film can beformed by sputtering or low pressure CVD.

[0219] Next, as the third step, through fine holes 13 are formed in thesilicon substrate 12 by a high aspect etching technique, such as deepetching, using the mask pattern 62 as a mask (FIG. 17 (C)). Theformation of the through fine holes 13 may be carried out, for example,by a high aspect etching technique, such as a Bosch process using anICP-RIE (inductively coupled plasma-reactive ion etching) device.According to the present invention, since there is no need to regulatethe depth of the fine holes 13, the process is simple. Further, inparticular, dry etching by ICP-RIE can significantly shorten the timenecessary for the formation of the through fine holes 13.

[0220] Next, as the fourth step, the mask pattern 62 is removed, andoxidation is carried out in a thermal oxidation furnace, whereby anabout 5000 to 10000 angstrom-thick silicon oxide layer 14 (an innersurface layer 15 b of silicon oxide) is formed on the wall surface ofthe through fine holes 13 and an about 5000 to 10000 angstrom-thicksilicon oxide layer 14 (an end face layer 15 c of silicon oxide) isformed on the silicon substrate 12 in its portion exposed within thesmall openings 61 a of the silicon nitride layer 61 (FIG. 18 (A)).

[0221] Next, as the fifth step, the silicon nitride layer 61 is removed(FIG. 18 (B)), and dry etching is carried out from the silicon substrate12 on its surface where the small openings 61 a of the silicon nitridelayer 61 have been formerly formed. In this dry etching, a part of thesilicon substrate 12 is etched using the silicon oxide layer 14 (the endface layer 15 c of silicon oxide) functions as a mask, whereby nozzlebases 15 a are formed integrally with the silicon substrate 12. The dryetching is stopped when the nozzle bases 15 a have been formed by adesired length. Thus, fine nozzles 15 protruded on the etching side ofthe silicon substrate 12 are prepared (FIG. 18 (C)). The wall thicknessof the nozzle bases 15 a is a difference in radius between the smallopenings 61 a and the fine openings 62 a and can be easily changed bythe design of the mask. In this connection, it should be noted that thedry etching in the fifth step may be carried out without removing thesilicon nitride layer 61.

[0222] Although the Bosch process utilizing an ICP-RIE device has beenused in the above high aspect etching, the present invention is notlimited to this only.

[0223] Further, in the production process of the fine nozzles, sincesites on the surface side, in which the mask pattern 62 has been formed,for example, by the deep etching in the third step (the etching accuracyis very high), are utilized on the front end side of the fine nozzles15, a plurality of fine nozzles 15 having an even opening diameter canbe formed.

Third Embodiment

[0224] The production process of fine nozzles according to the presentinvention will be described by taking the fine nozzles 5, in theapparatus 1′ for fine pattern formation shown in FIG. 3, as an examplewith reference to FIGS. 19 and 20.

[0225] At the outset, as the first step, the surface of a siliconsubstrate 2′ having <100> crystallographic orientation is cleaned, andan about 200 to 3000 angstrom-thick silicon nitride (Si₃N₄) layer 51′ isformed on the whole area of the silicon substrate 2′.

[0226] A photosensitive resist is then coated on the silicon nitridelayer 51′ in its portion located on the surface 2′A side of the siliconsubstrate 2′, and exposure through a predetermined photomask anddevelopment are carried out to form a resist pattern R. Subsequently,the silicon nitride layer 51′ is etched by RIE (reactive ion etching(process gas: CF₄ or SF₆)) using the resist pattern R as a mask to forma pattern having openings 51′a for taper (FIG. 19 (A)). The siliconnitride layer 51′ may be formed in the same manner as used in theformation of the silicon nitride layer 51. The depth, opening diameter,and shape of tapered concaves 3′a, which will be described later, aredetermined by the size and shape of the openings 51′a for taper in thesilicon nitride layer 51′. In general, the size of the opening for taperis preferably set in the range of 10 to 200 μm. The shape of the openingfor taper may be properly selected from square, circle and the like.

[0227] Next, as the second step, the silicon substrate 2′ is subjectedto crystallographically anisotropic etching with an aqueous potassiumhydroxide solution using the silicon nitride layer 51′ as a mask. Inthis etching, the silicon substrate 2′ in its portions exposed to theopenings 51 a′ for taper is etched in the direction of depth so that<111> crystallographic orientation appears. This etching is preferablycarried out, for example, until the apex of inverted quadrangularpyramid tapered openings is closed (i.e., until inverted quadrangularpyramid concaves are completely formed). As a result, tapered concaves3′a are formed on the surface 2′A side of the silicon substrate 2′ (FIG.19 (B)).

[0228] Next, as the third step, the resist pattern R is removed, and amask thin film 52′ is formed on the surface 2′A side and the backsurface 2′B side of the silicon substrate 2′. The mask thin film 52′ onthe back surface 2′B side of the silicon substrate 2′ remote from thetapered concaves 3′a is then patterned to form fine openings 52′a (FIG.19 (C)). This fine opening 52′a is formed so that the center of theopening substantially conforms to the center (apex) of the taperedconcave 3′a through the silicon substrate 2′. The diameter of openingsin fine holes 3 and fine nozzles 5, which will be described later, isdetermined by the size of the fine openings 52 ′a. In general, the sizeof the fine openings 52′a is preferably set in the range of 1 to 100 μm.

[0229] In addition to a metallic thin film, a resist, a thin film ofsilicon oxide or a combination of both the materials (resist/thin filmof silicon oxide) may be used as the mask thin film. Metallic thin filmsinclude thin films of aluminum, nickel, chromium and the like, and,preferably, the metallic thin film is formed to a thickness of about1000 to 2000 angstroms, for example, by sputtering or vacuum vapordeposition. For example, when aluminum is used as the metallic thinfilm, an aluminum etchant (mixed acid aluminum) may be used in theetching. Further, when the resist is formed as the mask thin film, spincoating may be used. In the case of silicon oxide, the thin film can beformed by sputtering or low pressure CVD.

[0230] Next, as the fourth step, through fine holes 3 are formed fromthe back surface 12′B side of the silicon substrate 2′ by a high aspectetching technique, such as deep etching, using the mask thin film 52′ asa mask (FIG. 20 (A)). The formation of the through fine holes 3 may becarried out, for example, by a high aspect etching technique, such asdry etching or deep etching, for example, by an ICP-RIE (inductivelycoupled plasma-reactive ion etching). In this deep etching, as soon asthe through fine holes 3 extended to the interior of the taperedconcaves 3′a, the mask thin film 52′ (mask thin film 52′ within thetapered concaves 3′a) formed on the surface 2′A side of the siliconsubstrate 2′ functions as a stopping layer. This can eliminate the needto control the depth of the fine holes 3 formed and can render theprocess simple. Further, in particular, dry etching by ICP-RIE cansignificantly shorten the time necessary for the formation of thethrough fine holes 3.

[0231] Next, as the fifth step, the mask thin film 52′ is removed, andoxidation is carried out in a thermal oxidation furnace to form an about5000 to 10000 angstrom-thick silicon oxide layer 4 on the wall surfaceof the through fine holes 3 and on the wall surface of the taperedconcaves 3′a (FIG. 20 (B)).

[0232] Next, as the sixth step, dry etching is carried out from the backsurface 2′B side of the silicon substrate 2′ remote from the taperedconcaves 3′a. In this dry etching, after the removal of the siliconnitride layer 51′, a part of the silicon substrate 2′ is etched toexpose the silicon oxide layer 4 formed on the inner wall of the throughfine holes 3. When this silicon oxide layer 4 has been exposed by adesired length, the dry etching is stopped to prepare fine nozzles 5formed of silicon oxide protruded on the etching side of the siliconsubstrate 2′ (FIG. 20 (C)).

[0233] Although the Bosch process utilizing an ICP-RIE device has beenused in the above high aspect etching, the present invention is notlimited to this only.

Fourth Embodiment

[0234] The production process of fine nozzles according to the presentinvention will be described by taking the fine nozzles 15, in theapparatus 11′ for fine pattern formation shown in FIG. 4, as an examplewith reference to FIGS. 21 and 22.

[0235] At the outset, as the first step, the surface of a siliconsubstrate 12′ having <100> crystallographic orientation is cleaned, andan about 200 to 3000 angstrom-thick silicon nitride (Si₃N₄) layer 61′ isformed on the whole area of the silicon substrate 12′.

[0236] A photosensitive resist is then coated on the silicon nitridelayer 61′ in its portion located on the surface 12″A side of the siliconsubstrate 12′, and exposure through a predetermined photomask anddevelopment are carried out to form a resist pattern R. Subsequently,the silicon nitride layer 61′ is etched by RIE (reactive ion etching(process gas: CF₄ or SF₆)) using the resist pattern R as a mask to forma pattern having openings 61′a for taper (FIG. 21 (A)). The siliconnitride layer 61′ may be formed in the same manner as used in theformation of the silicon nitride layer 51. The depth, opening diameter,and shape of tapered concaves 13′a, which will be described later, aredetermined by the size and shape of the openings 61′a for taper in thesilicon nitride layer 61′. In general, the size of the opening for taperis preferably set in the range of 10 to 200 μm. The shape of the openingfor taper may be properly selected from square, circle and the like.

[0237] Next, as the second step, the silicon substrate 12′ is subjectedto crystallographically anisotropic etching with an aqueous potassiumhydroxide solution using the silicon nitride layer 61′ as a mask. Inthis etching, the silicon substrate 12′ in its portions exposed to theopenings 61 a′ for taper is etched in the direction of depth so that<111> crystallographic orientation appears. This etching is preferablycarried out, for example, until the apex of inverted quadrangularpyramid tapered openings is closed (i.e., until inverted quadrangularpyramid concaves are completely formed). As a result, tapered concaves13′a are formed on the surface 12′A side of the silicon substrate 12′(FIG. 21 (B)).

[0238] Next, as the third step, a photosensitive resist is coated on thesilicon nitride layer 61′ on the back surface 12′B side of the siliconsubstrate 12′ remote from the tapered concaves 13′a, and exposurethrough a predetermined photomask and development are carried out toform a resist pattern. Subsequently, the silicon nitride layer 61′ isetched by RIE (reactive ion etching (process gas: CF₄ or SF₆)) using theresist pattern as a mask. Thereafter, the resist pattern is removed toform a pattern having small openings 61′b (FIG. 21 (C)). This smallopening 61′b is formed so that the center of the opening substantiallyconforms to the center (apex) of the tapered concave 13′a through thesilicon substrate 12′. The size (outer diameter) of nozzle bases, whichwill be described later, is determined by the size of the small openings61′b. In general, the opening diameter may be set in the range of 3 to120 μm.

[0239] Next, as the fourth step, a mask thin film 62′ is formed on thesurface 12′A side and the back surface 12′B side of the siliconsubstrate 12′. The mask thin film 62′ on the back surface 12′B side ofthe silicon substrate 12′ remote from the tapered concaves 13′a is thenpatterned to form fine openings 62′a (FIG. 20 (D)). This fine opening62′a is located within the small opening 61′b of the pattern of thesilicon nitride layer 61′, preferably located in the center portion ofthe small opening 61′b. The size of openings in fine holes 13 and finenozzles, which will be described later, is determined by the size of thefine openings 62′a. In general, the diameter of the openings may be setin the range of 1 to 100 μm.

[0240] In addition to a metallic thin film, a resist, a thin film ofsilicon oxide or a combination of both the materials (resist/thin filmof silicon oxide) may be used as the mask thin film. Metallic thin filmsinclude thin films of aluminum, nickel, chromium and the like, and,preferably, the metallic thin film is formed to a thickness of about1000 to 2000 angstroms, for example, by sputtering or vacuum vapordeposition. For example, when aluminum is used as the metallic thinfilm, an aluminum etchant (mixed acid aluminum) may be used in theetching. Further, when the resist is formed as the mask thin film, spincoating may be used. In the case of silicon oxide, the thin film can beformed by sputtering or low pressure CVD.

[0241] Next, as the fifth step, through fine holes 13 are formed in thesilicon substrate 12′, for example, by deep etching using the mask thinfilm 62′ as a mask from the back surface 12′B side of the siliconsubstrate 12′ (FIG. 22 (A)). The formation of the through fine holes 13may be carried out, for example, by a high aspect etching technique,such as dry etching or deep etching, for example, by an ICP-RIE(inductively coupled plasma-reactive ion etching). In this deep etching,as soon as the through fine holes 13 extended to the interior of thetapered concaves 13′a, the mask thin film 62′ (mask thin film 62′ withinthe tapered concaves 13′a) formed on the surface 12′A side of thesilicon substrate 12′ functions as a stopping layer. This can eliminatethe need to control the depth of the fine holes 13 formed and can renderthe process simple. Further, in particular, dry etching by ICP-RIE cansignificantly shorten the time necessary for the formation of thethrough fine holes 13.

[0242] Next, as the sixth step, the mask pattern 62′ is removed, andoxidation is carried out in a thermal oxidation furnace, whereby anabout 5000 to 10000 angstrom-thick silicon oxide layer 14 is formed onthe wall surface of the tapered concaves 13′, an about 5000 to 10000angstrom-thick silicon oxide layer 14 (an inner surface layer 15 b ofsilicon oxide) is formed on the wall surface of the through fine holes13, and an about 5000 to 10000 angstrom-thick silicon oxide layer 14 (anend face layer 15 c of silicon oxide) is formed on the silicon substrate12 in its portion exposed within the small openings 61 a of the siliconnitride layer 61 (FIG. 22 (B)).

[0243] Next, as the seventh step, the silicon nitride layer 61′ isremoved (FIG. 22 (C)), and dry etching is carried out from the backsurface 12′B side of the silicon substrate 12′ remote from the taperedconcaves 13′a. In this dry etching, a part of the silicon substrate 12′is etched using the silicon oxide layer 14 (the end face layer 15 c ofsilicon oxide) functions as a mask, whereby nozzle bases 15 a are formedintegrally with the silicon substrate 12′. The dry etching is stoppedwhen the nozzle bases 15 a have been formed by a desired length. Thus,fine nozzles 15 protruded on the etching side of the silicon substrate12′ are prepared (FIG. 22 (D)). The wall thickness of the nozzle bases15 a is a difference in radius between the small openings 61′a and thefine openings 62′a and can be easily changed by the design of the mask.In this connection, it should be noted that the dry etching in theseventh step may be carried out without removing the silicon nitridelayer 61′.

[0244] Although the Bosch process utilizing an ICP-RIE device has beenused in the above high aspect etching, the present invention is notlimited to this only.

Fifth Embodiment

[0245] The production process of fine nozzles according to the presentinvention will be described by taking the fine nozzles 5 in theapparatus 1″ for fine pattern formation shown in FIG. 5 as an examplewith reference to FIG. 23.

[0246] As the first step, an about 200 to 3000 angstrom-thick siliconnitride (Si₃N₄) layer 51″ is formed on the whole area of the siliconsubstrate 2 having a cleaned surface. Next, a mask thin film 51″ isformed on both surfaces of the silicon nitride layer 51″, and the maskthin film 51″ in its portion located on the surface 2″A side of thesilicon substrate 2″ is patterned to form a mask pattern having wideopenings 51″a. The mask thin film 51″ in its portion located on the backsurface 2″B side of the silicon substrate 2″ is patterned to form a maskpattern having fine openings 51″b (FIG. 23 (A)). The center of the wideopening 51″a is set so as to substantially conform to the center of thefine hole 51″b through the silicon substrate 2″.

[0247] The opening diameter of multistaged wide concaves 3″a, which willbe described later, is determined by the size and shape of the wideopening 51″a. In general, the size of the wide opening is preferably setin the range of 5 to 200 μm. Further, the diameter of openings in fineholes 3 and fine nozzles 5, which will be described later, is determinedby the size of the fine openings 51″b. In general, the size of the fineopenings is preferably set in the range of 1 to 100 μm.

[0248] The silicon nitride layer 51″ may be formed in the same manner asused in the silicon nitride layer 51.

[0249] In addition to a metallic thin film, a resist, a thin film ofsilicon oxide or a combination of both the materials (resist/thin filmof silicon oxide) may be used as the mask thin film. Metallic thin filmsinclude thin films of aluminum, nickel, chromium and the like, and,preferably, the metallic thin film is formed to a thickness of about1000 to 2000 angstroms, for example, by sputtering or vacuum vapordeposition. For example, when aluminum is used as the metallic thinfilm, an aluminum etchant (mixed acid aluminum) may be used in theetching. Further, when the resist is formed as the mask thin film, spincoating may be used. In the case of silicon oxide, the thin film can beformed by sputtering or low pressure CVD.

[0250] Fine holes 3 are formed by deep etching from the back surface 2″Bside of the silicon substrate 2″ (FIG. 23 (B)). The fine holes 3 may beformed, for example, by a high aspect etching technique, such as dryetching or deep etching, for example, by ICP-RIE (inductively coupledplasma-reactive ion etching). The formation of the fine holes 3 iscontinued until the depth reaches a predetermined level such that thefine holes do not yet completely pass through the silicon substrate 2″.In the present invention, in order to facilitate the regulation of thedepth of the fine holes 3, an SOI (silicon on insulator) wafer may beused as the silicon substrate 2″. The SOI wafer has a multilayerstructure comprising a silicon oxide thin film sandwiched between singlecrystal silicons. The silicon oxide thin film functions as a stoppinglayer in the deep etching. This can eliminate the need to control thedepth in the formation of the fine holes 3. When an SOI wafer having amultilayer structure, in which two silicon oxide thin films aresandwiched between single crystal silicons, is used, multistagedopenings, of which the number of stages is larger, can be formed.

[0251] Next, as the third step, wide concaves 3″a are formed from thesurface 2″ side of the silicon substrate 2″ by deep etching using themask pattern having wide openings 51″a as a mask (FIG. 23 (C)). The wideconcaves 3″a can be formed, for example, by high aspect etching, such asdry etching or deep etching, for example, by ICP-RIE (inductivelycoupled plasma-reactive ion etching). The formation of the wide concaves3″a is continued until the openings of the fine holes 3 appear withinthe wide concaves 3″a.

[0252] Next, as the fourth step, the mask thin film 51″ is removed, andoxidation is carried out in a thermal oxidation furnace to form an about5000 to 10000 angstrom-thick silicon oxide layer 4 on the wall surfaceof the fine holes 3 and on the wall surface of the wide concaves 3″a(FIG. 23 (D)).

[0253] Next, as the fifth step, dry etching is carried out from the backsurface 2″B side of the silicon substrate 2″ remote from the wideconcaves 3″a. In this dry etching, after the removal of the siliconnitride layer 51″, a part of the silicon substrate 2″ is etched toexpose the silicon oxide layer 4 formed on the inner wall of the throughfine holes 3. When this silicon oxide layer 4 has been exposed by adesired length, the dry etching is stopped to prepare fine nozzles 5formed of silicon oxide protruded on the etching side of the siliconsubstrate 2″ (FIG. 23 (E)).

[0254] Although the Bosch process utilizing an ICP-RIE device has beenused in the above high aspect etching, the present invention is notlimited to this only.

Sixth Embodiment

[0255] The production process of fine nozzles according to the presentinvention will be described by taking the fine nozzles 15 in theapparatus 11″ for fine pattern formation shown in FIG. 6 as an examplewith reference to FIGS. 24 and 25.

[0256] As the first step, an about 200 to 3000 angstrom-thick siliconnitride (Si₃N₄) layer 61″ is formed on the whole area of the siliconsubstrate 12″ having a cleaned surface. A photosensitive resist is thencoated on the silicon nitride layer 61″ in its portion located on theback surface 12″B side of the silicon substrate 12″, and exposurethrough a predetermined photomask and development are carried out toform a resist pattern. Subsequently, the silicon nitride layer 61 ″ isetched by RIE (reactive ion etching (process gas: CF₄ or SF₆)) using theresist pattern as a mask. Thereafter, the resist pattern is removed toform a pattern having small openings 61″a (FIG. 24 (A)). The siliconnitride layer 61 ″ may be formed in the same manner as used in theformation of the silicon nitride layer 51. The size (outer diameter) ofnozzle bases, which will be described later, is determined by the sizeof the small openings 61 ″a. In general, the opening diameter may be setin the range of 3 to 120 μm.

[0257] Next, as the second step, a mask thin film 62″ is formed on bothsurfaces so as to cover the silicon nitride layer 61″. Next, the maskthin film 62″ in its portion located on the back surface 12″B side ofthe silicon substrate 12″ is patterned by etching to form a mask patternhaving fine openings 62″a. Further, the mask thin film 62″ in itsportion located on the surface 12″A side of the silicon substrate 12″ ispatterned by etching to form a mask pattern having wide openings 62″b(FIG. 24 (B)). The fine openings 62″a are set so as to locate within thesmall openings 61″a of the pattern of the silicon nitride layer 61″,preferably are located in the center portion of the small openings 61″.The center of the wide opening 62″b is set so as to substantiallyconform to the center of the fine opening 62″a through the siliconsubstrate 12″.

[0258] The opening diameter of fine holes 13 and fine nozzles 15, whichwill be described later, is determined by the size of the fine openings62″a. In general, the size of the fine openings is preferably set in therange of 1 to 100 μm. Further, the opening diameter of multistaged wideconcaves 13″a, which will be described later, is determined by the sizeand shape of the wide openings 61″b. In general, the size of the wideopenings is preferably set in the range of 5 to 200 μm. The metallicthin film maybe formed of aluminum, nickel, chromium or the like and ispreferably formed to a thickness of about 1000 to 2000 angstroms, forexample, by sputtering or vacuum vapor deposition. For example, whenaluminum is used as the metallic thin film, an aluminum etchant (mixedacid aluminum) may be used for etching.

[0259] Next, as the third step, fine holes 13 are formed from the backsurface 12″B side of the silicon substrate 12″ by deep etching using themask pattern having fine openings 62″a as a mask (FIG. 24 (C)). The fineholes 13 may be formed, for example, by a high aspect etching technique,such as dry etching or deep etching, for example, by ICP-RIE(inductively coupled plasma-reactive ion etching). The formation of thefine holes 13 is continued until the depth reaches a predetermined levelsuch that the fine holes 13 do not yet completely pass through thesilicon substrate 12″. In the present invention, in order to facilitatethe regulation of the depth of the fine holes 13, an SOI (silicon oninsulator) wafer may be used as the silicon substrate 12″. The SOI waferhas a multilayer structure comprising a silicon oxide thin filmsandwiched between single crystal silicons. The silicon oxide thin filmfunctions as a stopping layer in the etching. When an SOI wafer having amultilayer structure, in which two silicon oxide thin films aresandwiched between single crystal silicons, is used, multistagedopenings, of which the number of stages is larger, can be formed.

[0260] Next, as the fourth step, wide concaves 13″a are formed from thesurface 12″A side of the silicon substrate 12″ by deep etching using themask pattern having wide openings 62″b as a mask (FIG. 24 (D)). The wideconcaves 13″a can be formed, for example, by high aspect etchingtechnique, such as dry etching or deep etching, for example, by ICP-RIE(inductively coupled plasma-reactive ion etching). The formation of thewide concaves 13″a is continued until the openings of the fine holes 13appear within the wide concaves 13″a.

[0261] Next, as the fifth step, the mask thin film 62″ is removed, andoxidation is carried out in a thermal oxidation furnace, whereby anabout 5000 to 10000 angstrom-thick silicon oxide layer 14 is formed onthe wall surface of the wide concaves 13″a, an about 5000 to 10000angstrom-thick silicon oxide layer 14 (an inner surface layer 15 b ofsilicon oxide) is formed on the wall surface of the fine holes 13, andan about 5000 to 10000 angstrom-thick silicon oxide layer 14 (an endface layer 15 c of silicon oxide) is formed on the silicon substrate 12″in its portion exposed within the small openings 61″a of the siliconnitride layer 61″ (FIG. 25 (A)).

[0262] Next, as the sixth step, the silicon nitride layer 61″ is removed(FIG. 25 (B)), and dry etching is carried out from the surface of thesilicon substrate 12″ in which the small openings 61″a in the siliconnitride layer 61″ has been formerly formed. In this dry etching, a partof the silicon substrate 12″ is etched using the silicon oxide layer 14(the end face layer 15 c of silicon oxide) functions as a mask, wherebynozzle bases 15 a are formed integrally with the silicon substrate 12″.The dry etching is stopped when the nozzle bases 15 a have been formedby a desired length. Thus, fine nozzles 15 protruded on the etching sideof the silicon substrate 12″ are prepared (FIG. 25 (C)). The wallthickness of the nozzle bases 15 a is a difference in radius between thesmall openings 61″a and the fine openings 62″a and can be easily changedby the design of the mask. In this connection, it should be noted thatthe dry etching in the sixth step may be carried out without removingthe silicon nitride layer 61.

[0263] Although the Bosch process utilizing an ICP-RIE device has beenused in the above high aspect etching, the present invention is notlimited to this only.

II-1 Apparatus for Fine Pattern Formation First Embodiment

[0264]FIG. 26 is a schematic cross-sectional view showing one embodimentof the apparatus for fine pattern formation according to the presentinvention, and FIG. 27 is a partially enlarged cross-sectional view of aportion around the front end of fine nozzles in the apparatus for finepattern formation shown in FIG. 26. In FIGS. 26 and 27,an apparatus 101for fine pattern formation comprises: a silicon substrate 102; finenozzles 105 protruded on the back surface 102B side of the siliconsubstrate 102; a reinforcing layer 106 which covers at least the frontend face 105 a and the outer face 105 b of the fine nozzles 105 and isfurther provided on the back surface 102B of the silicon substrate 102;a support member 107; an ink passage 108 for supplying ink to a spacebetween the silicon substrate 102 and the support member 107; and an inksupplying device 109 connected to the ink passage 108.

[0265] The silicon substrate 102 has a plurality of fine holes 103 whichextend through the silicon substrate 102 from the surface 102A side tothe back surface 102B side. Openings 103 a on the surface 102A side ofthe fine holes 103 are exposed to the space defined by the siliconsubstrate 102 and the support member 107. The silicon substrate 102 ispreferably formed of a single crystal of silicon, and the thickness ofthe silicon substrate 102 is preferably about 200 to 500 μm. Since thesilicon substrate 102 has a low coefficient of linear expansion of about2.6×10⁻⁶/K, a change in shape upon a temperature change is very small.

[0266] The fine holes 103 are cylindrical spaces which are circular in atransverse section perpendicular to the axial direction (a sectionparallel to the surface 102A of the silicon substrate 102) and arerectangular in a longitudinal section along the axial direction (asection perpendicular to the surface 102A of the silicon substrate 102).A silicon oxide layer 104 is provided on the wall surface of the fineholes 103. The thickness of the silicon oxide layer 104 is generallyabout 5000 to 10000 angstroms. In the embodiment shown in the drawing,the thickness of the silicon substrate 102, the opening diameter of thefine holes 103, the number of fine holes 103, the pitch of the fineholes 103 and the like are simplified for the explanation of theconstruction of the apparatus. The opening diameter of the fine holes103 may be properly set in the range of about 1 to 100 μm, and theaspect ratio of the fine holes 103 may be properly set in the range ofabout 1 to 100. The number of the fine holes 103 and the pitch of thefine holes 103 may be properly set according to the form of patternformed by the apparatus 101 for fine pattern formation, the method forpattern formation and the like. The pitch of the fine holes 103 ispreferably about 4 μm at the smallest.

[0267] The transverse sectional form of the fine holes 103 may be, inaddition to the above-described circular form, for example, anelliptical or polygonal form or a special form. Further, the fine holes103 may be a combination of two or more fine holes which are differentfrom each other in transverse sectional form. When the fine holes 103are elliptical or rectangular in transverse sectional form, the openingdiameter in the longitudinal direction may be properly set in the rangeof 5 to 500 μm. Further, regarding the longitudinal sectional form ofthe fine holes 103, in addition to the above-described rectangle, atrapezoid, wherein the back surface 102B side of the silicon substrate102 is narrowed (tapered), may be adopted.

[0268] The fine nozzles 105 are formed of silicon oxide, are providedintegrally with the silicon oxide layer 104 provided on the wall surfaceof the fine holes 103, and are in communication with the fine holes 103.The thickness of the fine nozzles 105 may be properly set in the rangeof 5000 to 10000 angstroms, the opening diameter may be properly set inthe range of 1 to 100 μm, and the protrusion level from the back surface102B of the silicon substrate 102B may be properly set in the range of 1to 150 μm. The provision of the fine nozzles 105 can prevent ink,ejected from the fine holes 103, from being deposited on the backsurface 102B side of the silicon substrate 102.

[0269] The reinforcing layer 106 reinforces the fine nozzles 105 toimprove the mechanical strength. The reinforcing layer 106 may be formedof a material, such as silicon oxide or phosphorus silicon glass. In theembodiment shown in the drawing, the reinforcing layer 106 covers thefront end face 105 a and outer face 105 b of the fine nozzles 105 and,in addition, is formed on a portion around the front end face of theinner face 105 c and on the back surface 102B of the silicon substrate102. The thickness of the reinforcing layer 106 may be at least twice,preferably 5 times that of the fine nozzles 105. In general, thethickness may be properly set in the range of 1 to 5 μm.

[0270] The opening diameter of the fine nozzles 105 can be substantiallyregulated by varying the thickness of the reinforcing layer 106 providedon the inner face 105 c of the fine nozzles 105. To this end, a methodmay be used wherein fine nozzles 105 having a predetermined openingdiameter are formed and the thickness of the reinforcing layer 106formed on the inner face of 105 c of the fine nozzles 105 is regulatedaccording to applications of the apparatus for fine pattern formation,properties of ink used and the like to form fine nozzles 105 having adesired opening diameter.

[0271] The reinforcing layer 106 may be formed, for example, by plasmaCVD, ion plating, or low pressure CVD. These film formation methods canrealize a high sneak level and thus are advantageous for the formationof the reinforcing layer 106 on the inner face 105 c of the fine nozzles105 having a three-dimensional structure.

[0272] In the embodiment shown in the drawing, the reinforcing layer 106is also formed on the back surface 102B of the silicon substrate 102. Inthe apparatus for fine pattern formation according to the presentinvention, the reinforcing layer 106 may not be provided in this site.

[0273] The support member 107 is provided on the surface 102A side ofthe silicon substrate 102, for supporting the silicon substrate 102. Inthe embodiment shown in the drawing, the support member 107 comprises: abase 107 a, which, as with the silicon substrate 102, is flat; a flangeportion 107 b provided on the periphery of the base 107 a; and anopening 107 c provided at the center of the base 107 a. The supportmember 107 is fixed to the peripheral portion of the surface 102A sideof the silicon substrate 102 by the flange portion 107 b. This canprovide a space for supplying ink to a portion between the siliconsubstrate 102 and the support member 107. The fixation of the supportmember 107 to the silicon substrate 102 through heat-resistant glass(not shown) can improve the working efficiency of later steps in theproduction of the apparatus for fine pattern formation.

[0274] This support member 107 is preferably formed of a material havinga coefficient of linear expansion in the range of one-tenth of thecoefficient of linear expansion of the silicon substrate 102 to 10 timesthe coefficient of linear expansion of the silicon substrate 102, forexample, Pyrex glass (tradename: Corning #7740, coefficient of linearexpansion=3.5×10⁻⁶/K) or SUS 304 (coefficient of linearexpansion=17.3×10⁻⁶/K). When these materials are used, the level of adistortion caused between the silicon substrate 102 and the supportmember 107 upon exposure to heat is very small. By virtue of this, theflatness of the silicon substrate 102 is maintained, and a patternhaving high positional accuracy can be formed.

[0275] The ink passage 108 is connected to the opening 107 c of thesupport member 107, and the other end of the ink passage 108 isconnected to an ink supplying device 109. In the embodiment shown in thedrawing, only one ink passage 108 in a pipe form is connected. In thiscase, a construction may also be adopted wherein a plurality of openings107 c, the number of which has been determined by taking intoconsideration, for example, the size of the apparatus 101 for finepattern formation and the evenness of ink flow pressure, are provided,and the ink passage 108 is connected to each opening 107 c. The supportmember 107 and the silicon substrate 102 may be fabricated so that theink passage is provided within the support member 107 and/or the siliconsubstrate 102.

[0276] The ink supplying device 109 is not particularly limited, and anyof a continuous supply pump, a constant rate supply pump and the likemay be used as the ink supplying device 109 and may be properly selectedaccording to the application of the apparatus 101 for fine patternformation.

[0277] In the above-described apparatus 101 for fine pattern formationaccording to the present invention, a plurality of fine nozzles 105,which have improved mechanical strength by virtue of the provision ofthe reinforcing layer 106 and thus are satisfactorily durable againstexternal impact and ink supply pressure, are provided on the backsurface of the silicon substrate 102, and ink can be ejected in a verysmall amount through these fine nozzles 105 with high accuracy. At thesame time, the deposition of ink onto the back surface of the siliconsubstrate 102 can be prevented. Further, the amount of ink ejected maybe set as desired by controlling the ink supplying device 109 to varythe amount of ink supplied. Therefore, a pattern can be stably writtendirectly on a pattern object with high accuracy.

[0278] The reinforcing layer 106, when formed of some material, hasimproved wettability by ink and sometime prevents stable ejection of inkdue to spreading of ink flowed from the fine nozzles 105 onto the backsurface 102B of the silicon substrate 102. To overcome this problem, inthe apparatus for fine pattern formation according to the presentinvention, a water-repellent layer may be provided at least on thereinforcing layer 106 provided on the outer face 105 b of the finenozzles 105 and on the back surface 102B of the silicon substrate 102.In FIG. 27, the water-repellent layer is indicated by an alternate longand short dash line. The water-repellent layer may be formed offlurocarbon. The fluorocarbon is preferably such that the ratio of thenumber of the carbon elements to the number of fluorine elements is inthe range of 1:1 to 1:2. This water-repellent layer may be formed, forexample, by plasma CVD, ion plating, or (thermal) CVD, and the thicknessof the water-repellent layer may be about 200 to 500 angstroms.

Second Embodiment

[0279]FIG. 28 is a schematic cross-sectional view showing anotherembodiment of the apparatus for fine pattern formation according to thepresent invention. In FIG. 28, an apparatus 111 for fine patternformation comprises: a silicon substrate 112, tapered concaves 113′aprovided on a surface 112A of the silicon substrate 112; fine nozzles115 protruded on the back surface 112B side of the silicon substrate112; a reinforcing layer 116 which covers at least the front end face115 a and outer face 115 b of the fine nozzles 115 and is furtherprovided on the back surface 112B of the silicon substrate 112; asupport member 117; an ink passage 118 for supplying ink to a spacebetween the silicon substrate 112 and the support member 117; and an inksupplying device 119 connected to the ink passage 118.

[0280] The silicon substrate 112 has fine holes 113 which extend throughthe silicon substrate 112 from the bottom of the plurality of taperedconcaves 113′a on the surface 112A side to the back surface 112B side.Openings 113 a on the surface 112A side of the fine holes 113 areexposed to the tapered concaves 113′a, and the tapered concaves 113′aare exposed to the space defined by silicon substrate 112 and thesupport member 117. Preferably, the silicon substrate 112 is formed of asingle crystal of silicon, in which the crystallographic orientation ofthe surface 112A and the back surface 112B is <100> face, and has athickness of about 200 to 500 μm. Since the silicon substrate 112 has alow coefficient of linear expansion of about 2.6×10⁻⁶/K, a change inshape upon a temperature change is very small.

[0281] A silicon oxide layer 114 is provided on the wall surface of thetapered concaves 113′a, and the thickness of the silicon oxide layer 114is generally about 5000 to 10000 angstroms. The taper in the concaves113′a may be in the form of any of an inverted cone, an invertedquadrangular pyramid and the like, and the depth of the concaves 113′amay be set in the range of about 5 to 150 μm, and the maximum openingdiameter may be set in the range of about 10 to 200 μm. For example,when the taper is in an inverted quadrangular pyramid form, the wallsurface of the concaves 113′a may be formed so that the angle of thewall surface of the concaves 113′a to the surface 112A of the siliconsubstrate 112 (<100> face) is 55 degrees. In the embodiment shown in thedrawing, the thickness of the silicon substrate 112, the number oftapered concaves 113′a, the pitch of the tapered concaves 113′a and thelike are simplified for the explanation of the construction of theapparatus. The number of the concaves 113′a and the pitch of theconcaves 113′a, together with the fine holes 113, may be properly setaccording to the form of pattern formed by the apparatus 111 for finepattern formation, the method for pattern formation and the like. Thepitch of the concaves 113′a is preferably about 10 μm at the smallest.

[0282] The fine holes 113 are cylindrical spaces which are circular in atransverse section perpendicular to the axial direction (a sectionparallel to the surface 112A of the silicon substrate 112) and arerectangular in a longitudinal section along the axial direction (asection perpendicular to the surface 112A of the silicon substrate 112).A silicon oxide layer 114 is provided on the wall surface of the fineholes 113 so as to be continued from the wall surface of the concaves113′a. In the embodiment shown in the drawing, the opening diameter ofthe fine holes 113, the number of fine holes 113, the pitch of the fineholes 113 and the like are simplified for the explanation of theconstruction of the apparatus. The opening diameter of the fine holes113 may be properly set in the range of about 1 to 100 μm, and theaspect ratio of the fine holes 113 may be properly set in the range ofabout 1 to 100. The number of the fine holes 113 and the pitch of thefine holes 113 may be properly set according to the form of patternformed by the apparatus 111 for fine pattern formation, the method forpattern formation and the like. The pitch of the fine holes 113 ispreferably about 10 μm at the smallest.

[0283] The transverse sectional form of the fine holes 113 may be, inaddition to the above-described circular form, for example, anelliptical or polygonal form or a special form. Further, the fine holes113 may be a combination of two or more fine holes which are differentfrom each other in transverse sectional form. When the fine holes areelliptical or rectangular in transverse sectional form, the openingdiameter in the longitudinal direction may be properly set in the rangeof 5 to 500 μm. Regarding the longitudinal sectional form of the fineholes 113, in addition to the above-described rectangle, a trapezoid,wherein the back surface 112B side of the silicon substrate 112 isnarrowed (for example, tapered at a smaller taper angle than that of thetapered concaves 113′a), may be adopted.

[0284] The fine nozzles 115 are formed of silicon oxide, are providedintegrally with the silicon oxide layer 114 provided on the wall surfaceof the fine holes 113, and are in communication with the fine holes 113.The thickness of the fine nozzles 115 may be properly set in the rangeof 5000 to 10000 angstroms, the opening diameter may be properly set inthe range of 1 to 100 μm, and the protrusion level from the back surface112B of the silicon substrate 112 may be properly set in the range of 1to 150 μm. The provision of such fine nozzles 115 can prevent ink,ejected from the fine holes 113, from being deposited on the backsurface 112B side of the silicon substrate 112.

[0285] The reinforcing layer 116 has the same construction as thereinforcing layer 106 and functions to reinforce the fine nozzles 115 toimprove the mechanical strength. Therefore, this reinforcing layer 116also may be formed using a material such as silicon oxide or phosphorussilicon glass, for example, by plasma CVD, ion plating, or low pressureCVD. In the embodiment shown in the drawing, the reinforcing layer 116covers the front end face 115 a and outer face 115 b of the fine nozzles115, is further provided on a portion around the front end face of theinner face 115 c and on the back surface 112B of the silicon substrate112. The thickness of the reinforcing layer 116 may be the same as thatof the reinforcing layer 106. Although the reinforcing layer 116 is alsoprovided on the back surface 112B of the silicon substrate 112, in theapparatus for fine pattern formation according to the present invention,the reinforcing layer 116 may not be provided in this site.

[0286] The support member 117, the ink passage 118, and the inksupplying device 119 are the same as the support member 107, the inkpassage 108, and the ink supplying device 109 in the apparatus 101 forfine pattern formation, and the explanation thereof will be omitted.

[0287] In the above-described apparatus 111 for fine pattern formationaccording to the present invention, by virtue of the provision oftapered concaves 113′a, the passage resistance of ink is reduced.Consequently, an ink having higher viscosity can be ejected in a verysmall amount with high accuracy through the plurality of fine nozzles115 provided on the back surface of the silicon substrate 112, and, atthe same time, the deposition of ink onto the back surface of thesilicon substrate 112 can be prevented. Further, the reinforcing layer116 improves the mechanical strength of the fine nozzles 115 and aresatisfactorily durable against external impact and ink supply pressure.Further, the amount of ink ejected may be set as desired by controllingthe ink supplying device 119 to vary the amount of ink supplied.Therefore, a pattern can be stably written directly on a pattern objectwith high accuracy.

[0288] Also in the apparatus 111 for fine pattern formation, as with theabove embodiment, the water-repellent layer may be provided at least onthe reinforcing layer 116 provided on the outer face 115 b of the finenozzles 115 and on the back surface 112B of the silicon substrate 112.As described above, the water-repellent layer may be formed offluorocarbon or the like.

Third Embodiment

[0289]FIG. 29 is a schematic cross-sectional view showing a stillfurther embodiment of the apparatus for fine pattern formation accordingto the present invention. In FIG. 29, an apparatus 121 for fine patternformation comprises: a silicon substrate 122; multistaged concaves 123′aprovided on a surface 122A of the silicon substrate 122; fine nozzles125 protruded on the back surface 122B side of the silicon substrate122; a reinforcing layer 126 which covers at least the front end face125 a and outer face 125 b of the fine nozzles 125 and is furtherprovided on the back surface 122B of the silicon substrate 122; asupport member 127; an ink passage 128 for supplying ink to a spacebetween the silicon substrate 122 and the support member 127; and an inksupplying device 129 connected to the ink passage 128.

[0290] The silicon substrate 122 has fine holes 123 which extend throughthe silicon substrate 122 from the bottom of the plurality ofmultistaged concaves 123′a on the surface 122A side to the back surface122B side. Openings 123 a on the surface 122A side of the fine holes 123are exposed to the concaves 123′a, and the concaves 123′a are exposed tothe space defined by the silicon substrate 122 and the support member127. According to this construction, the fine holes 123 each have atwo-staged concave opening comprising the opening 123 a as a fineopening and the concave 123′a as a wide opening.

[0291] The silicon substrate 122 may be formed of the same material asin the silicon substrate 102, and the thickness of the silicon substrate122 also may be set in the same range as that of the silicon substrate102. The silicon substrate 122 may be an SOI (silicon on insulator)wafer that has a thin film of silicon oxide, which is parallel to thesurface of the silicon substrate 122, at the boundary between theconcaves 123′a and the fine holes 123.

[0292] A silicon oxide layer 124 is provided on the wall surface of theconcaves 123′a, and the thickness of the silicon oxide layer 124 isgenerally about 5000 to 10000 angstroms. The concaves 123′a maybe in acylindrical, cubic, rectangular parallelopiped or other form, and thedepth of the concaves 123′a may be set in the range of about 1 to 150μm, and the opening diameter may be set in the range of about 5 to 200μm. In the embodiment shown in the drawing, the thickness of the siliconsubstrate 122, the number of concaves 123′a, the pitch of the concaves123′a and the like are simplified for the explanation of theconstruction of the apparatus. The number of the concaves 123′a and thepitch of the concaves 123′a, together with the fine holes 123, may beproperly set according to the form of pattern formed by the apparatus121 for fine pattern formation, the method for pattern formation and thelike. The pitch of the concaves 123′a is preferably about 10 μm at thesmallest. Further, in the embodiment shown in the drawing, as describedabove, two-staged openings of the opening 123 a as the fine opening andthe concave 123′a as the wide opening are adopted. Alternatively, three-or more staged openings may be adopted.

[0293] The fine holes 123 are cylindrical spaces which are circular in atransverse section perpendicular to the axial direction (a sectionparallel to the surface 122A of the silicon substrate 122) and arerectangular in a longitudinal section along the axial direction (asection perpendicular to the surface 122A of the silicon substrate 122).A silicon oxide layer 124 is provided on the wall surface of the fineholes 123 so as to be continued from the wall surface of the concaves123′a. In the embodiment shown in the drawing, the opening diameter ofthe fine holes 123, the number of fine holes 123, the pitch of the fineholes 123 and the like are simplified for the explanation of theconstruction of the apparatus. The opening diameter of the fine holes123 may be properly set in the range of about 1 to 100 μm, and theaspect ratio of the fine holes 123 may be properly set in the range ofabout 1 to 100. The number of the fine holes 123 and the pitch of thefine holes 123 may be properly set according to the form of patternformed by the apparatus 121 for fine pattern formation, the method forpattern formation and the like. The pitch of the fine holes 123 ispreferably about 10 μm at the smallest.

[0294] The transverse sectional form of the fine holes 123 may be, inaddition to the above-described circular form, for example, anelliptical or polygonal form or a special form. Further, the fine holes123 may be a combination of two or more fine holes which are differentfrom each other in transverse sectional form. When the fine holes areelliptical or rectangular in transverse sectional form, the openingdiameter in the longitudinal direction may be properly set in the rangeof 5 to 500 μm. Regarding the longitudinal sectional form of the fineholes 123, in addition to the above-described rectangle, a trapezoid,wherein the back surface 122B side of the silicon substrate 122 isnarrowed (tapered), may be adopted.

[0295] The fine nozzles 125 are formed of silicon oxide, are providedintegrally with the silicon oxide layer 124 provided on the wall surfaceof the fine holes 123, and are in communication with the fine holes 123.The thickness of the fine nozzles 125 may be properly set in the rangeof 5000 to 10000 angstroms, the opening diameter may be properly set inthe range of 1 to 100 μm, and the protrusion level from the back surface122B of the silicon substrate 122 may be properly set in the range of 1to 150 μm. The provision of such fine nozzles 125 can prevent ink,ejected from the fine holes 123, from being deposited on the backsurface 122B side of the silicon substrate 122.

[0296] The reinforcing layer 126 has the same construction as thereinforcing layer 106 and functions to reinforce the fine nozzles 125 toimprove the mechanical strength. Therefore, this reinforcing layer 126also may be formed using a material such as silicon oxide or phosphorussilicon glass, for example, by plasma CVD, ion plating, or low pressureCVD. In the embodiment shown in the drawing, the reinforcing layer 126covers the front end face 125 a and outer face 125 b of the fine nozzles125, is further provided on a portion around the front end face of theinner face 125 c and on the back surface 122B of the silicon substrate122. The thickness of the reinforcing layer 126 may be the same as thatof the reinforcing layer 106. Although the reinforcing layer 126 is alsoprovided on the back surface 122B of the silicon substrate 122, in theapparatus for fine pattern formation according to the present invention,the reinforcing layer 126 may not be provided in this site.

[0297] The support member 127, the ink passage 128, and the inksupplying device 129 are the same as the support member 107, the inkpassage 108, and the ink supplying device 109 in the apparatus 101 forfine pattern formation, and the explanation thereof will be omitted.

[0298] In the above-described apparatus 121 for fine pattern formationaccording to the present invention, by virtue of the provision ofmultistaged concaves 123′a, the passage resistance of ink is reduced.Consequently, an ink having higher viscosity can be ejected in a verysmall amount with high accuracy through the plurality of fine nozzles125 provided on the back surface of the silicon substrate 122, and, atthe same time, the deposition of ink onto the back surface of thesilicon substrate 122 can be prevented. Further, the reinforcing layer126 improves the mechanical strength of the fine nozzles 125 and aresatisfactorily durable against external impact and ink supply pressure.Further, the amount of ink ejected may be set as desired by controllingthe ink supplying device 129 to vary the amount of ink supplied.Therefore, a pattern can be stably written directly on a pattern objectwith high accuracy.

[0299] Also in the apparatus 121 for fine pattern formation, as with theabove embodiment, the water-repellent layer may be provided at least onthe reinforcing layer 126 provided on the outer face 125 b of the finenozzles 125 and on the back surface 122B of the silicon substrate 122.As described above, the water-repellent layer may be formed offluorocarbon or the like.

Fourth Embodiment

[0300]FIG. 30 is a schematic cross-sectional view showing anotherembodiment of the apparatus for fine pattern formation according to thepresent invention, and FIG. 31 is a bottom view of an apparatus for finepattern formation shown in FIG. 30. In FIGS. 30 and 31, the apparatus131 for fine pattern formation comprises: three continuous apparatusunits 131 a, 131 b, 131 c, that is, comprises a common silicon substrate132; a plurality of fine nozzles 135 protruded from the back surface132B of the silicon substrate 132; a reinforcing layer 136 which coversat least the front end face 135 a and outer face 135 b of the finenozzles 135 and is further provided on the back surface 132B of thesilicon substrate 132; three support members 137 provide on the surface132A side of the silicon substrate 132; three ink passages 138 forsupplying ink to spaces between the silicon substrate 132 and each ofthe support members 137; and ink supplying devices 139 a, 139 b, 139 cconnected to these respective ink passages 138.

[0301] For each of the apparatus units 131 a, 131 b, 131 c, the siliconsubstrate 132 has a plurality of fine holes 133 extending through thesilicon substrate 132 from the surface 132A side of the siliconsubstrate 132 to the back surface 132B side of the silicon substrate132, and the openings 133 a on the surface 132A side of the fine holes133 are exposed to the spaces defined by the silicon substrate 132 andthe support members 137. The silicon substrate 132 may be formed of thesame material as the above-described silicon substrate 102, and thethickness of the silicon substrate 132 also may be set in the same rangeas in the silicon substrate 102.

[0302] For each of the apparatus units 131 a, 131 b, 131 c, the fineholes 133 are provided in a pattern such that a plurality of fine holesare arranged along a predetermined direction (in a direction indicatedby an arrow A in FIG. 31) on an identical line. Openings 135 d in thefine nozzles 135, which will be described later, are also arranged inthe same manner as adopted in the fine holes 133. Specifically, in theapparatus unit 131 a, a plurality of lines of fine holes 133 arrangedalong the direction indicated by the arrow A are provided at pitch P1.Likewise, also in the apparatus unit 131 b, the apparatus unit 131 c, aplurality of lines of fine holes 133 are provided at pitch P1. The linesof the fine holes 133 in the apparatus unit 131 a, the lines of the fineholes 133 in the apparatus unit 131 b, and the lines of the fine holes133 in the apparatus unit 131 c are deviated from one another at pitchP2 (P1=3×P2). Therefore, in the whole apparatus 131 for fine patternformation, lines of fine holes in the apparatus units 131 a, 131 b, 131c are repeatedly arranged at pitch P2. The transverse sectional form,the longitudinal sectional form, the opening diameter, and the pitch ofthe fine holes 133 may be properly set in the same manner as in the fineholes 133. The silicon oxide layer 134 provided on the wall surface ofthe fine holes 133 may also be the same as the silicon oxide layer 104.In the embodiment shown in the drawing, for example, the thickness ofthe silicon substrate 132, the opening diameter, the number, and thepitch of the fine holes 133 provided with the silicon oxide layer 134have been simplified for facilitating the explanation of theconstruction of the apparatus.

[0303] The fine nozzles 135 have the same construction as the finenozzles 105, are formed integrally with the silicon oxide layer 134provided on the wall surface of the fine holes 133, and are incommunication with the fine holes 133. In the fine nozzles 135, thethickness, the opening diameter, and the protrusion level may be set inthe same respective ranges as those of the fine nozzles 105. Theprovision of such fine nozzles 135 can prevent ink, ejected from thefine holes 133, from being deposited on the back surface 132B side ofthe silicon substrate 132.

[0304] The reinforcing layer 136 has the same construction as thereinforcing layer 106 and functions to reinforce the fine nozzles 135 toimprove the mechanical strength. Therefore, this reinforcing layer 136also may be formed using a material such as silicon oxide or phosphorussilicon glass, for example, by plasma CVD, ion plating, or low pressureCVD. In the embodiment shown in the drawing, the reinforcing layer 136covers the front end face 135 a and outer face 135 b of the fine nozzles135, is further provided on a portion around the front end face of theinner face 135 c and on the back surface 132B of the silicon substrate132. The thickness of the reinforcing layer 136 may be the same as thatof the reinforcing layer 106. Although the reinforcing layer 136 is alsoprovided on the back surface 132B of the silicon substrate 132, in theapparatus for fine pattern formation according to the present invention,the reinforcing layer 136 may not be provided in this site.

[0305] The support member 137 is provided on the surface 132A side ofthe silicon substrate 132, for supporting the silicon substrate 132. Inthe embodiment shown in the drawing, as with the support member 107described above, the support member 137 comprises: a base 137 a, which,as with the silicon substrate 132, is flat; a flange portion 137 bprovided on the periphery of the base 137 a; and an opening 137 cprovided at the center of the base 137 a. The support member 137 isfixed to the surface 132A side of the silicon substrate 132 by theflange portion 137 b. This can provide a space for supplying ink to aportion between the silicon substrate 132 and each of the supportmembers 137. The fixation of the support member 137 to the siliconsubstrate 132 through heat-resistant glass (not shown) can improve theworking efficiency of later steps in the production of the apparatus forfine pattern formation. As with the support member 107 described above,this support member 137 is preferably formed of a material having acoefficient of linear expansion in the range of one-tenth of thecoefficient of linear expansion of the silicon substrate 132 to 10 timesthe coefficient of linear expansion of the silicon substrate 132.

[0306] The ink passages 138 are connected to the openings 137 c of therespective support members 137, and the other ends of the ink passages138 are connected respectively to ink supplying devices 139 a, 139 b,139 c. The ink supplying devices 139 a, 139 b, 139 c may be properlyselected from a continuous supply pump, a constant rate supply pump andthe like according to applications of the apparatus 131 for fine patternformation. In the embodiment shown in the drawing, only one ink passage138 is provided in each support member 137. In this case, a constructionmay also be adopted wherein a plurality of openings 137 c, the number ofwhich is determined by taking into consideration, for example, theevenness of ink flow pressure, are provided in a single support member137, and the ink passage 138 is connected to each opening 137 c. The inkpassage may be provided within the support member 137.

[0307] In this apparatus 131 for fine pattern formation according to thepresent invention, the fine nozzles 135 have high mechanical strength byvirtue of the provision of the reinforcing layer 136 and thus aresatisfactorily durable against external impact and ink supply pressure,and ink can be ejected through the plurality of fine nozzles 135 in avery small amount with high accuracy, and, at the same time, thedeposition of ink onto the back surface of the silicon substrate 132 canbe prevented. Different inks may be supplied respectively from the inksupplying devices 139 a, 139 b, 139 c to directly write a pattern with adesired ink for each of the apparatus units 131 a, 131 b, 131 c.Further, the amount of ink ejected may be set as desired by regulatingthe ink supplying devices 139 a, 139 b, 139 c to vary the amount of inksupplied. Furthermore, in the apparatus 131 for fine pattern formation,since the apparatus units 131 a, 131 b, 131 c are provided integrallywith one another, there is no need to join a plurality of apparatuses toone another and, in addition, the positional accuracy of the apparatusesis very high.

[0308] Also in the apparatus 131 for fine pattern formation, as with theabove embodiments, a water-repellent layer may be provided at least onthe reinforcing layer 136 provided on the outer face 135 b of the finenozzles 135 and on the back surface 132B of the silicon substrate 132.As described above, the water-repellent layer maybe formed of, forexample, fluorocarbon.

[0309] Also in the apparatus 131 for fine pattern formation, theopenings 133 a on the surface 132A side of the fine holes 133 may be ina tapered concave form or a multistaged concave form as described above.This can reduce the passage resistance of ink and can realize theejection of a very small amount of a higher-viscosity ink through theplurality of fine nozzles 135 with high accuracy.

Fifth Embodiment

[0310]FIG. 32 is a diagram showing still another embodiment of theapparatus for fine pattern formation according to the present invention,wherein FIG. 32 (A) is a schematic cross-sectional view and FIG. 32 (B)a bottom view. In FIG. 32, an apparatus 141 for fine pattern formationcomprises: a silicon substrate 142; a plurality of fine nozzles 145protruded from the back surface 142B of the silicon substrate 142; areinforcing layer 146 which covers at least the front end face 145 a andouter face 145 b of the fine nozzles 145 and is further provided on theback surface 142B of the silicon substrate 142; a support member 147provided on the surface 142A side of the silicon substrate 142; threeink passages 148 a, 148 b, 148 c provided within the silicon substrate142 and within the support member 147; and ink supplying devices 149 a,149 b, 149 c connected respectively to the ink passages.

[0311] The silicon substrate 142 is provided with a plurality of fineholes 143 which extend through the silicon substrate 142 from thesurface 142A side of the silicon substrate 142 to the back surface 142Bside of the silicon substrate 142, and openings 143 a on the surface142A side of the fine holes 143 each are exposed within any one of thethree ink passages 148 a, 148 b, 148 c provided in a groove form on thesurface 142A side. The silicon substrate 142 may be formed of the samematerial as the silicon substrate 102, and the thickness of the siliconsubstrate 142 may also be set in the same range as the silicon substrate102.

[0312] A plurality of fine holes 143 (openings 145 d in fine nozzles 145described later) are arranged on an identical line along a predetermineddirection (direction indicated by an arrow a in FIG. 32 (B)). Aplurality of these lines are provided at pitch P. In the embodimentshown in the drawing, six fine hole lines 143A, 143B, 143C, 143D, 143E,143F, in each of which a plurality of fine holes are arranged along adirection indicated by the arrow a, are provided at pitch P. Thetransverse sectional form, the longitudinal sectional form, the openingdiameter, and the pitch of the fine holes 143 may be properly set in thesame manner as in the fine holes 103. The silicon oxide layer 144provided on the wall surface of the fine holes 143 may also be the sameas the silicon oxide layer 104. In the embodiment shown in the drawing,for example, the opening diameter, the number, and the pitch of the fineholes 143 provided with the silicon oxide layer 144 have been simplifiedfor facilitating the explanation of the construction of the apparatus.

[0313] The fine nozzles 145 have the same construction as the finenozzles 105, are formed integrally with the silicon oxide layer 144provided on the wall surface of the fine holes 143, and are incommunication with the fine holes 143. In the fine nozzles 145, thethickness, the opening diameter, and the protrusion level may be set inthe same respective ranges as those of the fine nozzles 105. Theprovision of such fine nozzles 145 can prevent ink, ejected from thefine holes 143, from being deposited on the back surface 142B side ofthe silicon substrate 142.

[0314] The reinforcing layer 146 has the same construction as thereinforcing layer 106 and functions to reinforce the fine nozzles 145 toimprove the mechanical strength. Therefore, this reinforcing layer 146also may be formed of a material such as silicon oxide or phosphorussilicon glass. In the embodiment shown in the drawing, the reinforcinglayer 146 covers the front end face 145 a and outer face 145 b of thefine nozzles 145, is further provided on a portion around the front endface of the inner face 145 c. Further, the reinforcing layer 146 isprovided on the back surface 142B of the silicon substrate 142. Thethickness of the reinforcing layer 146 may be the same as that of thereinforcing layer 106. The reinforcing layer 146 may be formed, forexample, by plasma CVD, ion plating, or low pressure CVD. Although thereinforcing layer 146 is also provided on the back surface 142B of thesilicon substrate 142, in the apparatus for fine pattern formationaccording to the present invention, the reinforcing layer 146 may not beprovided in this site.

[0315] The support member 147 is a plate member which is provided on thesurface 142A side of the silicon substrate 142 to hold the siliconsubstrate 142, and ink passages 148 c are provided in a groove form inthe support member 147 on its silicon substrate 142 side.

[0316]FIG. 33 is a transverse sectional view taken on line A-A of thesilicon substrate 142 shown in FIG. 32 (A), and FIG. 34 a transversesectional view taken on line B-B of the support member 147 shown in FIG.32 (A).

[0317] As shown in FIG. 32 (A) and FIG. 33, in the silicon substrate142, an ink passage 148 a in a groove form is provided so as to connecteach of openings in fine hole lines 143A, 143D to the ink supplyingdevice 149 a, and an ink passage 148 b in a groove form is provided soas to connect each of the openings in fine hole lines 143B, 143E to theink supplying device 149 b. Further, an ink passage 148 c in a grooveform is provided on each of the openings in fine hole lines 143C, 143F.Further, as shown in FIG. 32 (A) and FIG. 34, in the support member 147,the ink passage 148 c in a groove form is provided so as to connect eachof the openings in the fine hole lines 143C, 143F to the ink supplyingdevice 149 c.

[0318] As shown in FIG. 35, three ink passages 148 a, 148 b, 148 cprovided between the support member 147 and the silicon substrate 142are independent of one another. As with the support member 107, thesupport member 147 is preferably formed of a material having acoefficient of linear expansion in the range of one-tenth of thecoefficient of linear expansion of the silicon substrate 142 to 10 timesthe coefficient of linear expansion of the silicon substrate 142.

[0319] The ends of the ink passages 148 a, 148 b, 148 c are connectedrespectively to the ink supplying devices 149 a, 149 b, 149 c. The inksupplying devices 149 a, 149 b, 149 c are not particularly limited, andany of a continuous supply pump, a constant rate supply pump and thelike may be used as the ink supplying device and may be properlyselected according to the application of the apparatus 141 for finepattern formation.

[0320] In the above-described apparatus 141 for fine pattern formationaccording to the present invention, a plurality of fine nozzles 145,which have improved mechanical strength by virtue of the provision ofthe reinforcing layer 146 and thus are satisfactorily durable againstexternal impact and ink supply pressure, are provided on the backsurface of the silicon substrate 142, and ink can be ejected in a verysmall amount through these fine nozzles 145 with high accuracy. At thesame time, the deposition of ink onto the back surface of the siliconsubstrate 142 can be prevented. The supply of different inksrespectively from the ink supplying devices 149 a, 149 b, 149 c permitsa pattern to be formed by direct writing with a desired ink for eachfine hole line grouped according to the ink passages 148 a, 148 b, 148 c(a group consisting of fine hole lines 143A and 143D, a group consistingof fine hole lines 143B and 143E, and a group consisting of fine holelines 143C and 143F), and is particularly advantageous for the formationof a stripe pattern which will be described later. Further, since theapparatus 141 for fine pattern formation does not comprise a pluralityof mutually connected apparatus units for respective inks, thepositional accuracy of each fine hole line is very high. Further, theamount of ink ejected can be set as desired by regulating the inksupplying devices 149 a, 149 b, 149 c to vary the amount of inksupplied.

[0321] Also in the apparatus 141 for fine pattern formation, as with theabove embodiments, a water-repellent layer may be provided at least onthe reinforcing layer 146 provided on the outer face 145 b of the finenozzles 145 and on the back surface 142B of the silicon substrate 142.As described above, the water-repellent layer may be formed of, forexample, fluorocarbon.

[0322] Also in the apparatus 141 for fine pattern formation, theopenings 143 a on the surface 142A side of the fine holes 143 may be ina tapered concave form or a multistaged concave form as described above.This can reduce the passage resistance of ink and can realize theejection of a very small amount of a higher-viscosity ink through theplurality of fine nozzles 145 with high accuracy.

Sixth Embodiment

[0323]FIG. 36 is a plan view showing a further embodiment of theapparatus for fine pattern formation according to the present invention.In FIG. 36, an apparatus 151 for fine pattern formation comprises: asilicon substrate 152; a plurality of fine nozzles protruded from theback surface of the silicon substrate 152; a reinforcing layer whichcovers at least the front end face and outer face of the fine nozzlesand is further provided on the back surface of the silicon substrate152; an ink passage for supplying ink to a space between the siliconsubstrate 152 and the support member; and an ink supplying deviceconnected to the ink passage. In FIG. 36, however, only the siliconsubstrate 152 is shown, and the fine nozzles, the reinforcing layer, thesupport member, the ink passage, and the ink supplying device are notshown.

[0324] The silicon substrate 152 has a plurality of fine holes 153 whichextend through the silicon substrate 152 from the surface 152A side ofthe silicon substrate 152 to the back surface side of the siliconsubstrate 152. The fine holes 153 are provided at positions such thatthe fine holes 153 constitute one pattern P, and a plurality of patternsP (10 patterns in the embodiment shown in the drawing) are provided onthe silicon substrate 152. In the drawing, the fine holes 153 are shownin only one pattern P, and, for the other patterns P, only the outlineis indicated by a chain line.

[0325] The silicon substrate 152 may be formed of the same material asused in the silicon substrate 102, and the thickness of the siliconsubstrate 152 also may be set in the same range as in the siliconsubstrate 102. The transverse sectional form, the longitudinal sectionalform, the opening diameter, and the pitch of the fine holes 153 may beproperly set in the same manner as in the fine holes 103. The fine holes153 have a silicon oxide layer on their wall surface, and this siliconoxide layer also may be the same as the silicon oxide layer 104.

[0326] A plurality of fine nozzles are protruded on the back surfaceside of the silicon substrate 152 so as to communicate with the fineholes 153. The fine nozzles may be the same as the fine nozzles 105.

[0327] The reinforcing layer may be formed so as to cover at least thefront end face and outer face of the fine nozzles and may be furtherprovided on the back surface of the silicon substrate 152. Thisreinforcing layer has the same construction as the reinforcing layer 106and functions to reinforce the fine nozzles and to improve themechanical strength. Therefore, this reinforcing layer also may beformed of, for example, a material such as silicon oxide or phosphorussilicon glass. The thickness of the reinforcing layer may be the same asthat of the reinforcing layer 106. The reinforcing layer may be formed,for example, by plasma CVD, ion plating, or low pressure CVD.

[0328] Further, in the silicon substrate 152, a support member having,on its periphery, a flange portion as described above in connection withthe support member 107 may be provided, and the flange portion in thesupport member may be fixed to the peripheral portion (a shaded regionin FIG. 36). The ink supply passage may be connected to the opening ofthe support member, and the ink supplying device may be connected to theother end of the ink supply passage.

[0329] In the above apparatus 151 for fine pattern formation, the finenozzles have high mechanical strength by virtue of the provision of thereinforcing layer thereon and thus are satisfactorily durable againstexternal impact and ink supply pressure, and ink can be ejected in avery small amount with high accuracy through the fine holes 153 (finenozzles) of the silicon substrate 152. A pattern in a form correspondingto the pattern P can be stably formed on a pattern object with highaccuracy by ejecting ink from the fine nozzles in the silicon substrate152 in a suitable amount such that inks ejected from mutually adjacentfine nozzles come into contact with each other on the pattern object, todirectly write a pattern. The amount of the ink ejected can be regulatedby controlling the ink supplying device.

[0330] Also in the above embodiment, all the plurality of patterns P arein an identical form. However, the present invention is not limited tothis only. For example, the pattern may be in a desired form, such as aconductor pattern for a printed wiring board.

[0331] In the apparatus 151 for fine pattern formation, as with theabove embodiments, a water-repellent layer may be provided at least onthe reinforcing layer provided on the outer face of the fine nozzles andon the back surface of the silicon substrate 152.

[0332] Also in the apparatus 151 for fine pattern formation, theopenings of the fine holes 153 on the surface side of the siliconsubstrate may be in a tapered concave form or a multistaged concave formas described in the above embodiments. This can reduce the passageresistance of ink and can realize the ejection of a very small amount ofa higher-viscosity ink through the plurality of fine nozzles with highaccuracy.

[0333] The above-described apparatus for fine pattern formationaccording to the present invention can be applied, for example, to theformation of a black matrix pattern or a color pattern for liquidcrystal displays, the formation of a phosphor layer for plasma displays,and the formation of a pattern in electroluminescence, as well as toconductor pattern formation for printed wiring boards.

II-2 Embodiments of Production of Apparatus for Fine Pattern Formation

[0334] Next, an embodiment of the production of the apparatus for finepattern formation according to the present invention will be describedby taking the apparatus 101 for fine pattern formation shown in FIG. 26as an example with reference to FIGS. 37 and 38.

[0335] At the outset, a silicon substrate 102 having a cleaned surfaceis oxidized in a thermal oxidation furnace to form an about 1 to 2μm-thick silicon oxide film 102′ on the whole area of the siliconsubstrate 102 (FIG. 37 (A)). The silicon oxide film 102′ may be formedby wet oxidation.

[0336] Next, a photosensitive resist is coated on one surface of thesilicon substrate 102, and exposure through a predetermined photomaskand development are carried out to form a resist pattern R (FIG. 37(B)). Next, the silicon oxide film 102′ is patterned, for example, withBHF 16 (a 22% aqueous ammonium monohydrodifluoride solution) using thisresist pattern R as a mask (FIG. 37 (C)). This patterning may also becarried out by dry etching using RIE (reactive ion etching) (processgas: CHF₃). In this patterning, the silicon oxide film 102′ in its site,on which the resist pattern R has not been provided, is removed.

[0337] Next, fine holes 103 are formed in the silicon substrate 102 to adesired depth using the patterned silicon oxide film 102′ as a mask(Fig.37 (D)). The fine holes 103 may be formed, for example, by high aspectetching such as ICP-RIE (inductively coupled plasma-reactive ionetching), wet etching, or deep RIE etching. The fine holes 103 areformed to a predetermined depth such that the holes do not yetcompletely pass through the silicon substrate 102.

[0338] Next, the resist pattern R and the silicon oxide film 102′ areremoved, and oxidation is again carried out in a thermal oxidationfurnace to form an about 5000 to 10000 angstrom-thick silicon oxidelayer 104 on the whole area of the silicon substrate 102 (FIG. 37 (E)).

[0339] Next, the support member 7 in its flange portion 107 b is fixedonto the peripheral portion on the surface side (on the fine hole formedside) of the silicon substrate 102 (FIG. 38 (A)). This fixation may becarried out, for example, by anodic bonding or epoxy adhesive. Prior tothe fixation of the support member 107, only the surface 102A of thesilicon substrate 102 may be immersed in BHF 16 to remove the siliconoxide layer 104. In this case, what is important is to avoid the removalof the silicon oxide layer 104 within the fine holes 103.

[0340] Next, only the outer surface side of the silicon substrate 102 isimmersed in BHF 16 to remove the silicon oxide layer 104 in this siteand thus to expose the back surface of the silicon substrate 102.Thereafter, etching is carried out with TMAH (tetramethylammoniumhydroxide) from the back surface side of the silicon substrate 102 (FIG.38 (B)). In this etching, since the silicon oxide layer 104 provided onthe inner wall of the fine holes 103 is resistant to TMAH, fine tubesformed of the silicon oxide layer 104 are protruded on the siliconsubstrate 102 side.

[0341] Next, the front end of the fine tubes formed of the silicon oxidelayer 104 is dissolved and removed with BHF 16 to form openings.Thereafter, the back surface side of the silicon substrate 102 is againetched with TMAH. When fine nozzles 105 formed of the silicon oxidelayer 104 having a predetermined length have been formed, etching withTMAH is completed (FIG. 38 (C)).

[0342] Next, at least the front end face 105 a and outer face 105 b ofthe fine nozzles 105 are covered with a reinforcing layer 106, and thereinforcing layer 106 is further formed on the back surface 102B of thesilicon substrate 102 (FIG. 38 (D)). The reinforcing layer 106 may beformed, for example, by plasma CVD, ion plating, or low pressure CVD. Inparticular, the plasma CVD can realize a high sneak level and thus isadvantageous in the formation of the reinforcing layer 106 on the innerface 105 c of the fine nozzles 105. An ink supplying device is thenconnected to the opening 107 c of the support member 107 through the inkpassage. Thus, the apparatus 101 for fine pattern formation according tothe present invention as shown in FIG. 26 can be prepared.

[0343] Besides etching with TMAH, dry process by RIE (reactive ionetching) may also be used for the etching of the back surface side ofthe silicon substrate 102.

[0344] Further, in the above embodiment, a silicon oxide film 102′ isformed. Instead of the silicon oxide film, a thin film of aluminum maybe formed by sputtering or the like for the preparation of the apparatusfor fine pattern formation. In this case, in the above step ofpatterning (FIG. 37 (C)), an aluminum etchant (mixed acid aluminum) maybe used.

[0345] Another embodiment of the production of the apparatus for finepattern formation according to the present invention will be describedby taking the apparatus 101 for fine pattern formation shown in FIG. 26as an example with reference to FIGS. 39 and 40.

[0346] An about 200 to 3000 angstrom-thick silicon nitride (Si₃N₄) layer102′ is first formed on the whole area of the silicon substrate 102having a cleaned surface (FIG. 39 (A)). The formation of the siliconnitride layer 102′ may be carried out, for example, by low pressure CVD.

[0347] Next, a mask thin film is formed on the silicon nitride layer102′ in its portion located on one surface of the silicon substrate 102.A photosensitive resist is coated on the mask thin film, and exposurethrough a predetermined photomask and development are carried out toform a resist pattern. Subsequently, the mask thin film is etched usingthe resist pattern as a mask. Thereafter, the resist pattern is removedto form a mask pattern 102″ having fine openings (FIG. 39 (B)). Thediameter of openings in fine holes 103 and fine nozzles 105 isdetermined by the size of the fine openings in the mask pattern 102″. Ingeneral, the size of the fine openings is preferably set in the range of1 to 100 μm. Metallic thin films usable herein include thin films ofaluminum, nickel, chromium and the like, and, preferably, the metallicthin film is formed to a thickness of about 1000 to 2000 angstroms, forexample, by sputtering or vacuum vapor deposition. For example, whenaluminum is used as the metallic thin film, an aluminum etchant (mixedacid aluminum) may be used in the etching.

[0348] Next, through fine holes 103 are formed in the silicon substrate102 by deep etching using the mask pattern 102″ as a mask (FIG. 39 (C)).The formation of the through fine holes 103 may be carried out, forexample, by a high aspect etching technique, such as dry etching or deepetching, for example, by ICP-RIE (inductively coupled plasma-reactiveion etching). According to this method, since there is no need toregulate the depth of the fine holes 103, the process is simple. Inparticular, dry etching by ICP-RIE can significantly shorten the timenecessary for the formation of the through fine holes 103.

[0349] Next, the mask pattern 102″ is removed, and oxidation is carriedout in a thermal oxidation furnace to form an about 5000 to 10000angstrom-thick silicon oxide layer 104 on the wall surface of thethrough fine holes 103 (FIG. 39 (D)).

[0350] Next, the silicon nitride layer 102′ is removed, and dry etchingis then carried out from one surface of the silicon substrate 102. Inthis dry etching, a part of the silicon substrate 102 is etched toexpose the silicon oxide layer 104 formed on the inner wall of thethrough fine holes 103. When this silicon oxide layer 104 has beenexposed by a desired length, the dry etching is stopped to prepare finenozzles 105 formed of silicon oxide protruded on the etching side of thesilicon substrate 102 (FIG. 40 (A)).

[0351] The dry etching is preferably carried out by ICP-RIE (inductivelycoupled plasma-reactive ion etching). However, the dry etching method isnot limited to ICP-RIE only.

[0352] In the dry etching, preferably, the surface of the siliconsubstrate 102, on which the mask pattern 102″ has been formerly formed,is selectively etched. The reason for this is as follows. Although thedeep etching is likely to cause some variation in shape of the etchingend (lower side in the drawing), the accuracy of etching of the siliconsubstrate 102 on its surface side, where the mask pattern 102″ has beenformed, is very high. When this site is used as the front end side ofthe fine nozzles 105, a plurality of fine nozzles 105 having an evenopening diameter can be more easily prepared.

[0353] Next, the support member 107 in its flange portion 107 b is fixedonto the peripheral portion on the surface side (on the fine hole formedside) of the silicon substrate 102 (FIG. 40 (B)). This fixation may becarried out, for example, by anodic bonding or epoxy adhesive.

[0354] Next, at least the front end face 105 a and outer face 105 b ofthe fine nozzles 105 are covered with a reinforcing layer 106, and thereinforcing layer 106 is further formed on the back surface 102B of thesilicon substrate 102 (FIG. 40 (C)). The reinforcing layer 106 maybeformed, for example, by plasma CVD, ion plating, or low pressure CVD.These film formation methods can realize a high sneak level and thus areadvantageous in the formation of the reinforcing layer 106 on the innerface 105 c of the fine nozzles 105. Thereafter, an ink supplying deviceis connected to the opening 107 c of the support member 107 through theink passage. Thus, the apparatus 101 for fine pattern formationaccording to the present invention as shown in FIG. 26 can be prepared.

[0355] Another embodiment of the production of the apparatus for finepattern formation according to the present invention will be describedby taking the apparatus 111 for fine pattern formation shown in FIG. 28as an example with reference to FIGS. 41 to 43.

[0356] At the outset, the surface of a silicon substrate 112 having<100> crystallographic orientation is cleaned, and an about 200 to 3000angstrom-thick silicon nitride (Si₃N₄) layer 112′ is formed on the wholearea of the silicon substrate 112.

[0357] A photosensitive resist is then coated on the silicon nitridelayer 112′ in its portion located on the surface 112A side of thesilicon substrate 112, and exposure through a predetermined photomaskand development are carried out to form a resist pattern R.Subsequently, the silicon nitride layer 112′ is etched by RIE (reactiveion etching (process gas: CF₄ or SF₆)) using the resist pattern R as amask to form a pattern having openings 112′a for taper (FIG. 41 (A)).The silicon nitride layer 112′ may be formed, for example, by lowpressure CVD. The depth, opening diameter, and shape of tapered concaves113′a, which will be described later, are determined by the size andshape of the openings 112′a for taper in the silicon nitride layer 112′.In general, the size of the opening for taper is preferably set in therange of 10 to 200 μm. The shape of the opening for taper may beproperly selected from square, circle and the like.

[0358] Next, the silicon substrate 112 is subjected tocrystallographically anisotropic etching with an aqueous potassiumhydroxide solution using the silicon nitride layer 112′ as a mask. Inthis etching, the silicon substrate 112 in its portions exposed to theopenings 112′ for taper is etched in the direction of depth so that<111> crystallographic orientation appears. This etching is preferablycarried out, for example, until the apex of inverted quadrangularpyramid tapered openings is closed (i.e., until inverted quadrangularpyramid concaves are completely formed). As a result, tapered concaves113′a are formed on the surface 112A side of the silicon substrate 112(FIG. 41 (B)).

[0359] Next, the resist pattern R is removed, and a mask thin film 112″is formed on the surface 112A side and the back surface 112B side of thesilicon substrate 112. The mask thin film 112″ on the back surface 112Bside of the silicon substrate 112 remote from the tapered concaves 113′ais then patterned to form fine openings 112″a (FIG. 41 (C)). This fineopening 112″a is formed so that the center of the opening substantiallyconforms to the center (apex) of the tapered concave 113′a through thesilicon substrate 112. The diameter of openings in fine holes 113 andfine nozzles 115, which will be described later, is determined by thesize of the fine openings 112′a. In general, the size of the fineopenings 112″a is preferably set in the range of 1 to 100 μm. Metallicthin films usable herein include thin films of aluminum, nickel andchromium. The metallic thin film is preferably formed to a thickness ofabout 1000 to 2000 angstroms, for example, by sputtering or vacuum vapordeposition. For example, when aluminum is used as the metallic thinfilm, an aluminum etchant (mixed acid aluminum) may be used in theetching.

[0360] Next, through fine holes 113 are formed in the silicon substrate112 by deep etching using the mask thin film 112″ as a mask from theback surface 112B side of the silicon substrate 112 (FIG. 42 (A)). Theformation of the through fine holes 113 may be carried out, for example,by a high aspect etching technique, such as dry etching or deep etching,for example, by an ICP-RIE (inductively coupled plasma-reactive ionetching). In this deep etching, as soon as the through fine holes 113extended to the interior of the tapered concaves 113′a, the mask thinfilm 112″ (mask thin film 112″ within the tapered concaves 113′a) formedon the surface 112A side of the silicon substrate 112 functions as astopping layer. This can eliminate the need to control the depth of thefine holes 113 formed and can render the process simple. Further, inparticular, dry etching by ICP-RIE can significantly shorten the timenecessary for the formation of the through fine holes 113.

[0361] Next, the mask thin film 112″ is removed, and oxidation iscarried out in a thermal oxidation furnace to form an about 5000 to10000 angstrom-thick silicon oxide layer 114 on the wall surface of thethrough fine holes 113 and on the wall surface of the tapered concaves113′a (FIG. 42 (B)).

[0362] Next, the silicon nitride layer 112′ is removed, and dry etchingis carried out from the back surface 112B side of the silicon substrate112 remote from the tapered concaves 113′a. In this dry etching, a partof the silicon substrate 112 is etched to expose the silicon oxide layer114 formed on the inner wall of the through fine holes 113. When thissilicon oxide layer 114 has been exposed by a desired length, the dryetching is stopped to prepare fine nozzles 115 formed of silicon oxideprotruded on the etching side of the silicon substrate 112 (FIG. 42(C)).

[0363] Although the Bosch process utilizing an ICP-RIE device has beenused in the above high aspect etching, the etching method is not limitedto this only.

[0364] Next, the support member 117 in its flange portion 117 b is fixedonto the peripheral portion on the surface side (on the tapered concaveformed side) of the silicon substrate 112 (FIG. 43 (A)). This fixationmay be carried out, for example, by anodic bonding or epoxy adhesive.

[0365] Next, at least the front end face 115 a and outer face 115 b ofthe fine nozzles 115 are covered with a reinforcing layer 116, and thereinforcing layer 116 is further formed on the back surface 112B of thesilicon substrate 112 (FIG. 43 (B)). The reinforcing layer 116 may beformed, for example, by plasma CVD, ion plating, or low pressure CVD.These film formation methods can realize a high sneak level and thus areadvantageous in the formation of the reinforcing layer 116 on the innerface 115 c of the fine nozzles 115. Thereafter, an ink supplying deviceis connected to the opening 117 c of the support member 117 through theink passage. Thus, the apparatus 111 for fine pattern formationaccording to the present invention as shown in FIG. 28 can be prepared.

[0366] A further embodiment of the production of the apparatus for finepattern formation according to the present invention will be describedby taking the apparatus 121 for fine pattern formation shown in FIG. 29as an example with reference to FIGS. 44 and 45.

[0367] At the outset, an about 200 to 3000 angstrom-thick siliconnitride (Si₃N₄) layer 122′ is formed on the whole area of the siliconsubstrate 122 having a cleaned surface. Next, a mask thin film 122″ isformed on both surfaces of the silicon nitride layer 122′, and the maskthin film 122″ in its portion located on the surface 122A side of thesilicon substrate 122 is patterned to form a mask pattern having wideopenings 122″a. The mask thin film 122″ in its portion located on theback surface 122B side of the silicon substrate 122 is patterned to forma mask pattern having fine openings 122″b (FIG. 44 (A)). The center ofthe wide opening 122″a is set so as to substantially conform to thecenter of the fine opening 122″b through the silicon substrate 122.

[0368] The opening diameter of multistaged wide concaves 123′a, whichwill be described later, is determined by the size and shape of the wideopening 122″a. In general, the size of the wide opening is preferablyset in the range of 5 to 200 μm. Further, the diameter of openings infine holes 123 and fine nozzles 125, which will be described later, isdetermined by the size of the fine openings 122″b. In general, the sizeof the fine openings is preferably set in the range of 1 to 100 μm.

[0369] The silicon nitride layer 122′ may be formed in the same manneras used in the formation of the silicon nitride layer 112′. In additionto a metallic thin film, a resist, a thin film of silicon oxide or acombination of both the materials (resist/thin film of silicon oxide)may be used as the mask thin film. Metallic thin films include thinfilms of aluminum, nickel, chromium and the like, and, preferably, themetallic thin film is formed to a thickness of about 1000 to 2000angstroms, for example, by sputtering or vacuum vapor deposition. Forexample, when aluminum is used as the metallic thin film, an aluminumetchant (mixed acid aluminum) may be used in the etching. Further, whenthe resist is formed as the mask thin film, spin coating may be used. Inthe case of silicon oxide, the thin film can be formed by sputtering orlow pressure CVD.

[0370] Fine holes 123 are then formed by deep etching using the maskpattern having the fine openings 122″b as a mask from the back surface122B side of the silicon substrate 122 (FIG. 44 (B)). The fine holes 123may be formed, for example, by a high aspect etching technique, such asdry etching or deep etching, for example, by ICP-RIE (inductivelycoupled plasma-reactive ion etching). The formation of the fine holes123 is continued until the depth reaches a predetermined level such thatthe fine holes 123 do not yet completely pass through the siliconsubstrate 122. In the present invention, in order to facilitate theregulation of the depth of the fine holes 123, an SOI (silicon oninsulator) wafer may be used as the silicon substrate 122. The SOI waferhas a multilayer structure comprising a silicon oxide thin filmsandwiched between single crystal silicons. The silicon oxide thin filmfunctions as a stopping layer in the deep etching. This can eliminatethe need to control the depth in the formation of the fine holes 123.When an SOI wafer having a multilayer structure, in which two siliconoxide thin films are sandwiched between single crystal silicons, isused, multistaged openings, of which the number of stages is larger, canbe formed.

[0371] Next, wide concaves 123′a are formed from the surface 122A sideof the silicon substrate 122 by deep etching using the mask patternhaving wide openings 122″a as a mask (FIG. 44 (C)). The wide concaves123′a can be formed, for example, by a high aspect etching technique,such as a Bosch process using an ICP-RIE (inductively coupledplasma-reactive ion etching) device. The formation of the wide concaves123′a is continued until the openings of the fine holes 123 appearwithin the wide concaves 123′a.

[0372] Next, the mask thin film 122″ is removed, and oxidation iscarried out in a thermal oxidation furnace to form an about 5000 to10000 angstrom-thick silicon oxide layer 124 on the wall surface of thefine holes 123 and on the wall surface of the wide concaves 123′a (FIG.44 (D)).

[0373] Next, the silicon nitride layer 122′ is removed, and dry etchingis carried out from the back surface 122B side of the silicon substrate122 remote from the wide concaves 123′. In this dry etching, a part ofthe silicon substrate 122 is etched to expose the silicon oxide layer124 formed on the inner wall of the through fine holes 123. When thissilicon oxide layer 124 has been exposed by a desired length, the dryetching is stopped to prepare fine nozzles 125 formed of silicon oxideprotruded on the etching side of the silicon substrate 122 (FIG. 45(A)).

[0374] Although the Bosch process utilizing an ICP-RIE device has beenused in the above high aspect etching, the etching method is not limitedto this only.

[0375] Next, the support member 127 in its flange portion 127 b is fixedonto the peripheral portion on the surface side (on the multistagedconcave formed side) of the silicon substrate 122 (FIG. 45 (B)). Thisfixation may be carried out, for example, by anodic bonding or epoxyadhesive.

[0376] Next, at least the front end face 125 a and outer face 125 b ofthe fine nozzles 125 are covered with a reinforcing layer 126, and thereinforcing layer 126 is further formed on the back surface 122B of thesilicon substrate 122 (FIG. 45 (C)). The reinforcing layer 126 may beformed, for example, by plasma CVD, ion plating, or low pressure CVD.These film formation methods can realize a high sneak level and thus areadvantageous in the formation of the reinforcing layer 126 on the innerface 125 c of the fine nozzles 125. Thereafter, an ink supplying deviceis connected to the opening 127 c of the support member 127 through theink passage. Thus, the apparatus 121 for fine pattern formationaccording to the present invention as shown in FIG. 29 can be prepared.

II-3 Formation of Fine Pattern

[0377] Next, the formation of a fine pattern using the apparatus forfine pattern formation according to the present invention will bedescribed.

[0378]FIG. 46 is a diagram illustrating one embodiment of fine patternformation using the apparatus 131 for fine pattern formation accordingto the present invention. In FIG. 46, while supplying ink A, ink B, andink C respectively from the ink supplying devices 139 a, 139 b, 139 c inthe apparatus 131 for fine pattern formation according to the presentinvention through the ink passages 138, a pattern object S is scannedrelative to the apparatus 131 for fine pattern formation in apredetermined direction (a direction indicated by an arrow A). Thescanning direction A is identical to the arrangement direction A (seeFIG. 31) of the fine holes in the apparatus 131 for fine patternformation. In this case, the space between the silicon substrate 132 inthe apparatus 131 for fine pattern formation and the pattern object Smay be set in the range of about 0.1 to 5 mm.

[0379] According to this construction, inks ejected from the finenozzles 135 in the silicon substrate 132 form, by direct writing, astripe pattern comprising ink A, ink B, and ink C which have beenrepeatedly sequenced in that order on the pattern object S. In thiscase, the pitch of the stripes is P2. In this stripe pattern, since onestripe is formed of ink ejected from the plurality of fine nozzles on anidentical line, even when the amount of ink ejected from the individualfine nozzles is small, the scanning speed of the pattern object S can beincreased to increase the pattern formation speed. This stripe patternis formed with very high accuracy by varying the diameter of the fineholes 133 or the fine nozzles 135 (including the case where thethickness of the reinforcing layer 136 provided on the inner face of thefine nozzles is changed) to control the ejection width of ink, and theprocess is simpler than the conventional photolithography.

[0380] When the pattern object S is flexible, preferably, a back-uproller is disposed on the back surface of the pattern object S so as toface the apparatus 131 for fine pattern formation. In this case, thepattern object S is carried while applying tension to the pattern objectS by the back-up roller to directly write a pattern on the patternobject S.

[0381] Next, FIG. 47 is a diagram showing one embodiment of fine patternformation using the apparatus 151 for fine pattern formation accordingto the present invention. In FIG. 47, the apparatus 151 for fine patternformation (only the silicon substrate 152 is shown in the embodiment inthe drawing) is disposed at a predetermined position of the patternobject S, a given amount of ink supplied from the ink passage is ejectedthrough the fine holes (fine nozzles) onto the pattern object to form apattern.

[0382] Thereafter, the pattern object S is carried by a predetermineddistance in a direction indicated by an arrow A, and the same patternformation as described above is carried out. A desired pattern P can beformed on the pattern object S by repeating the above procedure. Thespace between the silicon substrate 152 in the apparatus 151 for finepattern formation and the pattern object S may be set in the range ofabout 0.1 to 5 mm.

[0383] Further, a printed wiring board can be simply produced withoutreplying on photolithography, for example, by forming the pattern P,formed of the plurality of fine holes (fine nozzles) in the apparatus151 for fine pattern formation, as a conductor pattern of a printedwiring board, and using a conductor paste as ink.

III-1 Apparatus for Fine Pattern Formation First Embodiment

[0384]FIG. 48 is a schematic cross-sectional view showing one embodimentof the apparatus for fine pattern formation according to the presentinvention. In FIG. 48, the apparatus 201 for fine pattern formationcomprises: a silicon substrate 202; a main electrode 206 provided on thesurface 202A side of the silicon substrate 202; a support member 208; acounter electrode 207 provided on the back surface 202B side of thesilicon substrate 202 while leaving a predetermined space between themain electrode 206 and the counter electrode 207; an ink passage 209 forsupplying ink to a space between the silicon substrate 202 and thesupport member 208; and an ink supplying device 210 connected to the inkpassage 209.

[0385] The silicon substrate 202 has a plurality of fine holes 203 whichextend through the silicon substrate 202 from the surface 202A side tothe back surface 202B side. Openings 203 a on the surface 202A side ofthe fine holes 203 are exposed to the space defined by the siliconsubstrate 202 and the support member 208. The silicon substrate 202 ispreferably formed of a single crystal of silicon, and the thickness ofthe silicon substrate 202 is preferably about 200 to 500 μm. Since thesilicon substrate 202 has a low coefficient of linear expansion of about2.6×10⁻⁶/K, a change in shape upon a temperature change is very small.

[0386] The fine holes 203 are cylindrical spaces which are circular in atransverse section perpendicular to the axial direction (a sectionparallel to the surface 202A of the silicon substrate 202) and arerectangular in a longitudinal section along the axial direction (asection perpendicular to the surface 202A of the silicon substrate 202).A silicon oxide layer 204 is provided on the wall surface of the fineholes 203. The thickness of the silicon oxide layer 204 is generallyabout 5000 to 10000 angstroms. In the embodiment shown in the drawing,the thickness of the silicon substrate 202, the opening diameter of thefine holes 203 provided with the silicon oxide layer 204, the number offine holes 203, the pitch of the fine holes 203 and the like aresimplified for the explanation of the construction of the apparatus. Theopening diameter of the fine holes 203 may be properly set in the rangeof about 1 to 100 μm, and the aspect ratio of the fine holes 203 may beproperly set in the range of about 1 to 100. The number of the fineholes 203 and the pitch of the fine holes 203 may be properly setaccording to the form of pattern formed by the apparatus 201 for finepattern formation, the method for pattern formation and the like. Thepitch of the fine holes 203 is preferably about 2 μm at the smallest.

[0387] The transverse sectional form of the fine holes 203 may be, inaddition to the above-described circular form, for example, anelliptical or polygonal form or a special form. Further, the fine holes203 may be a combination of two or more fine holes which are differentfrom each other or one another in transverse sectional form. When thefine holes 203 are elliptical or rectangular in transverse sectionalform, the opening diameter in the longitudinal direction may be properlyset in the range of 5 to 500 μm. Further, regarding the longitudinalsectional form of the fine holes 203, in addition to the above-describedrectangle, a trapezoid, wherein the back surface 202B side of thesilicon substrate 202 is narrowed (tapered), may be adopted.

[0388]FIG. 49 is a plan view illustrating a main electrode 206 providedon the surface 202A side of a silicon substrate 202, in such a statethat a support member 208 has been removed. As shown in FIG. 49, themain electrode 206 has an opening 206 a and is provided so as tosurround a plurality of fine holes 203 (5 fine holes in the embodimentshown in the drawing). The main electrode 206 is formed of a conductivethin film of aluminum, copper, chromium, gold, silver, silicon or thelike and may generally be provided on the silicon substrate 202 sidethrough an electrically insulating thin film of polyimide or the like.

[0389] The counter electrode 207 may be in an electrically grounded orfloating state. In order to write finer lines, the grounded state ispreferred. In the embodiment shown in the drawing, the counter electrode207 is in an electrically grounded state and, when a predeterminedvoltage has been applied to the main electrode 206, functions to causean electric field between the counter electrode 207 and the mainelectrode 206. This counter electrode 207 may be, for example, in a drumor flat plate form. In this case, a pattern object is disposed in aspace between the silicon substrate 202 and the counter electrode 207,or disposed on the counter electrode 207, and, as described later, apattern can be formed by direct writing. When the pattern object iselectrically conductive, the pattern object may serve also as thecounter electrode. When writing of finer lines is desired, the counterelectrode 207 is preferably in a grounded state. The distance betweenthe pattern object and the silicon substrate 202 may be set in the rangeof about 50 to 500 μm.

[0390] The counter electrode 207 may be formed of a conductive material,such as SUS 304, copper, or aluminum. Alternatively, the counterelectrode 207 may have a construction such that a conductive thin filmhas been formed on a nonconductive material such as glass or a resinmaterial.

[0391] The support member 208 is provided on the surface 202A side ofthe silicon substrate 202, for supporting the silicon substrate 202. Inthe embodiment shown in the drawing, the support member 208 comprises: abase 208 a, which, as with the silicon substrate 202, is flat; a flangeportion 208 b provided on the periphery of the base 208 a; and anopening 208 c provided at the center of the base 208 a. The supportmember 208 is fixed to the peripheral portion of the surface 202A sideof the silicon substrate 202 by the flange portion 208 b. This canprovide a space for supplying ink to a portion between the siliconsubstrate 202 and the support member 208 (ink supply space). Thefixation of the support member 208 to the silicon substrate 202 throughheat-resistant glass (not shown) can improve the working efficiency oflater steps in the production of the apparatus for fine patternformation.

[0392] This support member 208 is preferably formed of a material havinga coefficient of linear expansion in the range of one-tenth of thecoefficient of linear expansion of the silicon substrate 202 to 10 timesthe coefficient of linear expansion of the silicon substrate 202, forexample, Pyrex glass (tradename: Corning #7740, coefficient of linearexpansion=3.5×10⁻⁶/K) or SUS 304 (coefficient of linearexpansion=17.3×10⁻⁶/K). When these materials are used, the level of adistortion caused between the silicon substrate 202 and the supportmember 208 upon exposure to heat is very small. By virtue of this, theflatness of the silicon substrate 202 is maintained, and a patternhaving high positional accuracy can be formed.

[0393] The ink passage 209 is connected to the opening 208 c of thesupport member 208, and the other end of the ink passage 209 isconnected to an ink supplying device 210. In the embodiment shown in thedrawing, only one ink passage 209 in a pipe form is connected. In thiscase, a construction may also be adopted wherein a plurality of openings208 c, the number of which has been determined by taking intoconsideration, for example, the size of the apparatus 201 for finepattern formation and the evenness of ink flow pressure, are provided,and the ink passage 209 is connected to each opening 208 c. The supportmember 208 and the silicon substrate 202 may be fabricated so that theink passage is provided within the support member 208 and/or the siliconsubstrate 202.

[0394] The ink supplying device 210 is not particularly limited, and anyof a continuous supply pump, a constant rate supply pump and the likemay be used as the ink supplying device 210 and may be properly selectedaccording to the application of the apparatus 201 for fine patternformation.

[0395] In the above apparatus 201 for fine pattern formation accordingto the present invention, since a combination of an electric field,formed between the main electrode 206 and the counter electrode 207,with an ink supply pressure from the ink supplying device 210 is used asink ejection means, ink can be ejected in a very small amount with highaccuracy at a low ink supply pressure through the fine holes 203 in thesilicon substrate 202. When ink is present in the ink supply space, theformation of the electric field suffices for the ejection of the inkand, in this case, ink supply pressure is not required. Here lowpressure refers to a pressure of not more than 5 psi. This is true ofthe following description of the present invention.

[0396] Further, the width and amount of ink ejected from the fine holes203 can be regulated by varying the strength of field formed between themain electrode 206 and the counter electrode 207. Therefore, ink can beejected through the fine holes 203 having a predetermined openingdiameter in desired ejection width and ejection amount. Further, theamount of ink ejected can be set as desired by varying the amount of inksupplied. The width and amount of ink ejected through the fine holes 203can be regulated by varying both the field strength and the ink supplypressure. Therefore, a pattern can be stably directly written on apattern object with high accuracy.

Second Embodiment

[0397]FIG. 50 is a schematic cross-sectional view showing anotherembodiment of the apparatus for fine pattern formation according to thepresent invention. As shown in FIG. 50, the basic structure of theapparatus 211 for fine pattern formation has the same as that of theapparatus 201 for fine pattern formation, and nozzles 215 are formed inopenings 213 b in fine holes 213 on the back surface 212B side of thesilicon substrate 212. The nozzles 215 are formed of silicon oxide andare formed integrally with the silicon oxide layer 214, and theprotrusion level may be properly set in the range of 10 to 400 μm. Theprovision of this type of nozzles 215 can prevent the deposition of inkejected through the fine holes 213 onto the back surface 212B side ofthe silicon substrate 212.

[0398] The main electrode 216 may also be provided on the back surface212B side of the silicon substrate 212. FIG. 51 is a rear viewillustrating a main electrode in a frame form provided on the backsurface 212B side of the silicon substrate 212. As shown in FIG. 51, Themain electrode 216 has an opening 216 a provided so as to surround theplurality of nozzles 215. The space between the main electrode 216 andthe counter electrode 217 may be set in the range of about 50 to 500 μm.

[0399] In the apparatus 211 for fine pattern formation according to thepresent invention, when a combination of an electric field formedbetween the main electrode 216 and the counter electrode 217 with thesupply pressure of ink from the ink supplying device 220 is used as inkejection means, ink can be ejected in a very small amount with highaccuracy without increasing the ink supply pressure. Thus, the damage ofthe nozzles 215 can be prevented.

[0400] Further, in the apparatus 211 for fine pattern formation, areinforcing layer may be provided for improving the mechanical strengthof the nozzles 215. FIG. 52 is a schematic cross-sectional view showingan embodiment wherein the apparatus 211 for fine pattern formation has areinforcing layer. As shown in FIG. 52, the reinforcing layer 215′covers the front end face and outer face of the nozzles 215 and isfurther provided on the inner face on a portion around the front endface. Further, the reinforcing layer 215′ is formed on the back surface212B of the silicon substrate 212. The thickness of the reinforcinglayer 215′ may be at least twice, preferably at least five times, thatof the nozzles 215. In general, the thickness of the reinforcing layer215′ may be properly set in the range of 1 to 5 μm. The reinforcinglayer 215′ may be formed of, for example, a material such as siliconoxide or phosphorus silicon glass.

[0401] The opening diameter of the nozzles 215 may be substantiallyregulated by varying the thickness of the reinforcing layer 215′provided on the inner face of the nozzles 215. Therefore, a method maybe adopted wherein nozzles 215 having a predetermined opening diameteris formed and the thickness of the reinforcing layer 215′ provided onthe inner face of the nozzles 215 is regulated, for example, accordingto applications of the apparatus for fine pattern formation and theproperties of ink used to form nozzles 215 having a desired openingdiameter.

[0402] The reinforcing layer 215′ may be formed, for example, by plasmaCVD, ion plating, or low pressure CVD. These film formation methods canrealize a high sneak level and thus are advantageous for the formationof the reinforcing layer on the inner face of the nozzles 215 having athree-dimensional structure.

[0403] In the embodiment shown in the drawing, the reinforcing layer215′ is also formed on the back surface 212B of the silicon substrate212. In the apparatus for fine pattern formation according to thepresent invention, however, the reinforcing layer 215′ may not beprovided in this site.

Third Embodiment

[0404]FIG. 53 is a schematic cross-sectional view showing still anotherembodiment of the apparatus for fine pattern formation according to thepresent invention. In FIG. 53, an apparatus 221 for fine patternformation comprises: a silicon substrate 222; tapered concaves 223′aprovided on the surface 222A of the silicon substrate 222; nozzles 225protruded on the back surface 222B side of the silicon substrate 222; amain electrode 226 provided on the surface 222A side of the siliconsubstrate 222; a counter electrode 227 provided at predeterminedintervals on the back surface 222B side of the silicon substrate 222; asupport member 228; an ink passage 229 for supplying ink to a spacebetween the silicon substrate 222 and a support member 228; and an inksupplying device 230 connected to the ink passage 229.

[0405] The silicon substrate 222 has fine holes 223 which extend throughthe silicon substrate 222 from the bottom of the plurality of taperedconcaves 223′a on the surface 222A side to the back surface 222B side.The openings 223 a on the surface 222A side of the fine holes 223 areexposed to the tapered concaves 223′a. The tapered concaves 223′a areexposed to a space defined by the silicon substrate 222 and the supportmember 228. The silicon substrate 222 is preferably a single crystal ofsilicon such that the surface 222A and the back surface 222B have <100>crystallographic orientation. The thickness of the silicon substrate 222is preferably about 200 to 500 μm. The silicon substrate 222 has a lowcoefficient of linear expansion of about 2.6×10⁻⁶/K and thus is lesslikely to undergo a change in shape upon a change in temperature.

[0406] A silicon oxide layer 224 is provided on the wall surface of thetapered concaves 223′a, and the thickness of the silicon oxide layer 224is generally about 5000 to 10000 angstroms. The taper in the concaves223′a may be in the form of any of an inverted cone, an invertedquadrangular pyramid and the like, and the depth of the concaves 223′amay be set in the range of about 5 to 150 μm, and the maximum openingdiameter may be set in the range of about 10 to 200 μm. For example,when the taper is in an inverted quadrangular pyramid form, the wallsurface of the concaves 223′a may be formed so that the angle of thewall surface of the concaves 223′a to the surface 222A of the siliconsubstrate 222 (<100> face) is 55 degrees. In the embodiment shown in thedrawing, the thickness of the silicon substrate 222, the number oftapered concaves 223′a, the pitch of the tapered concaves 223′a and thelike are simplified for the explanation of the construction of theapparatus. The number of the concaves 223′a and the pitch of theconcaves 223′a, together with the fine holes 223, may be properly setaccording to the form of pattern formed by the apparatus 221 for finepattern formation, the method for pattern formation and the like. Thepitch of the concaves 223′a is preferably about 15 μm at the smallest.

[0407] The fine holes 223 are cylindrical spaces which are circular in atransverse section perpendicular to the axial direction (a sectionparallel to the surface 222A of the silicon substrate 222) and arerectangular in a longitudinal section along the axial direction (asection perpendicular to the surface 222A of the silicon substrate 222).A silicon oxide layer 224 is provided on the wall surface of the fineholes 223 so as to be continued from the wall surface of the concaves223′a. In the embodiment shown in the drawing, the opening diameter ofthe fine holes 223, the number of fine holes 223, the pitch of the fineholes 223 and the like are simplified for the explanation of theconstruction of the apparatus. The opening diameter of the fine holes223 may be properly set in the range of about 1 to 100 μm, and theaspect ratio of the fine holes 223 may be properly set in the range ofabout 1 to 100. The number of the fine holes 223 and the pitch of thefine holes 223 may be properly set according to the form of patternformed by the apparatus 221 for fine pattern formation, the method forpattern formation and the like. The pitch of the fine holes 223 ispreferably about 15 μm at the smallest.

[0408] The transverse sectional form of the fine holes 223 may be, inaddition to the above-described circular form, for example, anelliptical or polygonal form or a special form. Further, the fine holes223 may be a combination of two or more fine holes which are differentfrom each other in transverse sectional form. When the fine holes areelliptical or rectangular in transverse sectional form, the openingdiameter in the longitudinal direction may be properly set in the rangeof 5 to 500 μm. Regarding the longitudinal sectional form of the fineholes 223, in addition to the above-described rectangle, a trapezoid,wherein the back surface 222B side of the silicon substrate 222 isnarrowed (for example, tapered at a smaller taper angle than that of thetapered concaves 223′a), may be adopted.

[0409] The nozzles 225 are formed of silicon oxide, are providedintegrally with the silicon oxide layer 224 provided on the wall surfaceof the fine holes 223, and are in communication with the fine holes 223.The thickness of the nozzles 225 may be properly set in the range of5000 to 10000 angstroms, the opening diameter may be properly set in therange of 1 to 100 μm, and the protrusion level from the back surface222B of the silicon substrate 222 may be properly set in the range of 1to 150 μm. The provision of such nozzles 225 can prevent ink, ejectedfrom the fine holes 223, from being deposited on the back surface 222Bside of the silicon substrate 222.

[0410] The main electrode 226 has an opening and is provided so as tosurround a plurality of tapered concaves 223′a (five tapered concaves inthe embodiment shown in the drawing). The main electrode 226 is formedof a conductive thin film of aluminum, copper, chromium, gold, silver,silicon or the like and may generally be provided on the siliconsubstrate 222 side through an electrically insulating thin film ofpolyimide or the like.

[0411] The counter electrode 227 may be in an electrically grounded orfloating state. The distance between the counter electrode 227 and thesilicon substrate 222 may be set in the range of about 50 to 500 μm. Thecounter electrode 227 may be formed of a conductive material, such asSUS 304, copper, or aluminum. Alternatively, the counter electrode mayhave a construction such that a conductive thin film has been formed ona nonconductive material such as glass or a resin material.

[0412] The main electrode 226 may also be provided on the back surface222B side of the silicon substrate 222. In this case, the distancebetween the main electrode 226 and the counter electrode 227 may be setin the range of about 50 to 500 μm.

[0413] The support member 228, the ink passage 229, and the inksupplying device 230 are the same as the support member 208, the inkpassage 209, and the ink supplying device 210 in the apparatus 201 forfine pattern formation, and the explanation thereof will be omitted.

[0414] In this apparatus 221 for fine pattern formation according to thepresent invention, by virtue of the provision of tapered concaves 223′a,the passage resistance of ink can be reduced, and an ink having higherviscosity can be ejected through the plurality of nozzles 225 on theback surface of the silicon substrate 222 in a very small amount withhigh accuracy, and, at the same time, the deposition of ink onto theback surface of the silicon substrate 222 can be prevented. Further,when a combination of an electric field formed between the mainelectrode 226 and the counter electrode 227 with the supply pressure ofink from the ink supplying device 230 is used as ink ejection means, inkcan be ejected in a very small amount with high accuracy withoutincreasing the ink supply pressure. This can prevent the damage of thenozzles 225.

[0415] Also in the apparatus 221 for fine pattern formation, areinforcing layer may be provided on the nozzles 225. Further, as withthe apparatus 201 for fine pattern formation, the nozzles may not be ina protruded form.

Fourth Embodiment

[0416]FIG. 54 is a schematic cross-sectional view showing a stillfurther embodiment of the apparatus for fine pattern formation accordingto the present invention. In FIG. 54, an apparatus 231 for fine patternformation comprises: a silicon substrate 232; multistaged concaves 233′aprovided on a surface 232A of the silicon substrate 232; nozzles 235protruded on the back surface 232B side of the silicon substrate 232; amain electrode 236 provided on the surface 232A side of the siliconsubstrate 232; a counter electrode 237 provided on the back surface 232Bside of the silicon substrate 232 while leaving a predetermined spacebetween the main electrode 236 and the counter electrode 237; a supportmember 238; an ink passage 239 for supplying ink to a space between thesilicon substrate 232 and a support member 238; and an ink supplyingdevice 240 connected to the ink passage 239.

[0417] The silicon substrate 232 has fine holes 233 which extend throughthe silicon substrate 232 from the bottom of the plurality ofmultistaged concaves 233′a on the surface 232A side to the back surface232B side. Openings 233 a on the surface 232A side of the fine holes 233are exposed to the concaves 233′a, and the concaves 233′a are exposed tothe space defined by the silicon substrate 232 and the support member238. According to this construction, the fine holes 233 each have atwo-staged concave opening comprising the opening 233 a as a fineopening and the concave 233′a as a wide opening.

[0418] The silicon substrate 232 may be formed of the same material asin the silicon substrate 202, and the thickness of the silicon substrate232 also may be set in the same range as that of the silicon substrate202. The silicon substrate 232 may be an SOI (silicon on insulator)wafer that has a thin film of silicon oxide, which is parallel to thesurface of the silicon substrate 232, at the boundary between theconcaves 233′a and the fine holes 233.

[0419] A silicon oxide layer 234 is provided on the wall surface of theconcaves 233′a, and the thickness of the silicon oxide layer 234 isgenerally about 5000 to 10000 angstroms. The concaves 233′a may be in acylindrical, cubic, rectangular parallelopiped or other form, and thedepth of the concaves 233′a may be set in the range of about 1 to 150μm, and the opening diameter may be set in the range of about 5 to 200μm. In the embodiment shown in the drawing, the thickness of the siliconsubstrate 232, the number of concaves 233′a, the pitch of the concaves233′a and the like are simplified for the explanation of theconstruction of the apparatus. The number of the concaves 233′a and thepitch of the concaves 233′a, together with the fine holes 233, may beproperly set according to the form of pattern formed by the apparatus231 for fine pattern formation, the method for pattern formation and thelike. The pitch of the concaves 233′a is preferably about 10 μm at thesmallest. Further, in the embodiment shown in the drawing, as describedabove, two-staged openings of the opening 233 a as the fine opening andthe concave 233′a as the wide opening are adopted. Alternatively, three-or more staged openings may be adopted.

[0420] The fine holes 233 are cylindrical spaces which are circular in atransverse section perpendicular to the axial direction (a sectionparallel to the surface 232A of the silicon substrate 232) and arerectangular in a longitudinal section along the axial direction (asection perpendicular to the surface 232A of the silicon substrate 232).A silicon oxide layer 234 is provided on the wall surface of the fineholes 233 so as to be continued from the wall surface of the concaves233′a. In the embodiment shown in the drawing, the opening diameter ofthe fine holes 233, the number of fine holes 233, the pitch of the fineholes 233 and the like are simplified for the explanation of theconstruction of the apparatus. The opening diameter of the fine holes233 may be properly set in the range of about 1 to 100 μm, and theaspect ratio of the fine holes 233 may be properly set in the range ofabout 1 to 100. The number of the fine holes 233 and the pitch of thefine holes 233 may be properly set according to the form of patternformed by the apparatus 231 for fine pattern formation, the method forpattern formation and the like. The pitch of the fine holes 233 ispreferably about 10 μm at the smallest.

[0421] The transverse sectional form of the fine holes 233 may be, inaddition to the above-described circular form, for example, anelliptical or polygonal form or a special form. Further, the fine holes233 may be a combination of two or more fine holes which are differentfrom each other in transverse sectional form. When the fine holes areelliptical or rectangular in transverse sectional form, the openingdiameter in the longitudinal direction may be properly set in the rangeof 5 to 500 μm. Regarding the longitudinal sectional form of the fineholes 233, in addition to the above-described rectangle, a trapezoid,wherein the back surface 232B side of the silicon substrate 232 isnarrowed (tapered), may be adopted.

[0422] The nozzles 235 are formed of silicon oxide, are providedintegrally with the silicon oxide layer 234 provided on the wall surfaceof the fine holes 233, and are in communication with the fine holes 233.The thickness of the nozzles 235 may be properly set in the range of5000 to 10000 angstroms, the opening diameter may be properly set in therange of 1 to 100 μm, and the protrusion level from the back surface232B of the silicon substrate 232 may be properly set in the range of 1to 150 μm. The provision of such nozzles 235 can prevent ink, ejectedfrom the fine holes 233, from being deposited on the back surface 232Bside of the silicon substrate 232.

[0423] The main electrode 236 has an opening and is provided so as tosurround a plurality of multistaged concaves 233′a (five multistagedconcaves in the embodiment shown in the drawing). The main electrode 236is formed of a conductive thin film of aluminum, copper, chromium, gold,silver, silicon or the like and may generally be provided on the siliconsubstrate 232 side through an electrically insulating thin film ofpolyimide or the like.

[0424] The counter electrode 237 may be in an electrically grounded orfloating state. The distance between the counter electrode 237 and thesilicon substrate 232 may be set in the range of about 50 to 500 μm. Thecounter electrode 237 may be formed of a conductive material, such asSUS 304, copper, or aluminum. Alternatively, the counter electrode 237may have a construction such that a conductive thin film has been formedon a nonconductive material such as glass or a resin material.

[0425] The main electrode 236 may also be provided on the back surface232B side of the silicon substrate 232. In this case, the distancebetween the main electrode 236 and the counter electrode 237 may be setin the range of about 50 to 500 μm.

[0426] The support member 238, the ink passage 239, and the inksupplying device 240 are the same as the support member 208, the inkpassage 209, and the ink supplying device 210 in the apparatus 201 forfine pattern formation, and the explanation thereof will be omitted.

[0427] In this apparatus 231 for fine pattern formation according to thepresent invention, by virtue of the provision of multistaged concaves233′a, the passage resistance of ink can be reduced, and an ink havinghigher viscosity can be ejected through the plurality of nozzles 235 onthe back surface of the silicon substrate 232 in a very small amountwith high accuracy, and, at the same time, the deposition of ink ontothe back surface of the silicon substrate 232 can be prevented. Further,when a combination of an electric field formed between the mainelectrode 236 and the counter electrode 237 with the supply pressure ofink from the ink supplying device 240 is used as ink ejection means, inkcan be ejected in a very small amount with high accuracy withoutincreasing the ink supply pressure. This can prevent the damage of thenozzles 235.

[0428] Also in the apparatus 231 for fine pattern formation, areinforcing layer may be provided on the nozzles 235. Further, as withthe apparatus 201 for fine pattern formation, the nozzles may not be ina protruded form.

Fifth Embodiment

[0429]FIG. 55 is a schematic cross-sectional view showing still anotherembodiment of the apparatus for fine pattern formation according to thepresent invention, and FIG. 56 is a bottom view of an apparatus for finepattern formation shown in FIG. 55. In FIGS. 55 and 56, the apparatus241 for fine pattern formation comprises three continuous apparatusunits 241 a, 241 b, 241 c, that is, comprises: a common siliconsubstrate 242; thee main electrodes 246 a, 246 b, 246 c provided on thesurface 242A side of the silicon substrate 242; three support members248; a counter electrode 247 provided on the back surface 242B side ofthe silicon substrate 242 while leaving a predetermined space betweenthe main electrodes and the counter electrode 247; three ink passages249 for supplying ink to a space between the silicon substrate 242 andeach of the support members 248; and ink supplying devices 250 a, 250 b,250 c connected to the ink passages 249.

[0430] For each of the apparatus units 241 a, 241 b, 241 c, the siliconsubstrate 242 has a plurality of fine holes 243 extending through thesilicon substrate 242 from the surface 242A side of the siliconsubstrate 242 to the back surface 242B side of the silicon substrate 22,and the openings 243 a on the surface 242A side of the fine holes 243are exposed to the spaces defined by the silicon substrate 242 and thesupport members 248. The silicon substrate 242 may be formed of the samematerial as the above-described silicon substrate 202, and the thicknessof the silicon substrate 242 also may be set in the same range as in thesilicon substrate 202.

[0431] For each of the apparatus units 241 a, 241 b, 241 c, the fineholes 243 are provided in a pattern such that a plurality of fine holesare arranged along a predetermined direction (in a direction indicatedby an arrow A in FIG. 56) on an identical line. Specifically, in theapparatus unit 241 a, a plurality of lines of fine holes 243 arrangedalong the direction indicated by the arrow A are provided at pitch P1.Likewise, also in the apparatus unit 241 b, the apparatus unit 241 c, aplurality of lines of fine holes 243 are provided at pitch P1. The linesof the fine holes 243 in the apparatus unit 241 a, the lines of the fineholes 243 in the apparatus unit 241 b, 241 c are deviated from oneanother at pitch P2 (P1=3×P2). Therefore, in the whole apparatus 241 forfine pattern formation, lines of fine holes in the apparatus units 241a, 241 b, 241 c are repeatedly arranged at pitch P2. The transversesectional form, the longitudinal sectional form, the inner diameter, andthe pitch of the fine holes 243 may be properly set in the same manneras in the fine holes 203. The silicon oxide layer 244 provided on thewall surface of the fine holes 243 may also be the same as the siliconoxide layer 204. In the embodiment shown in the drawing, for example,the opening diameter, the number, and the pitch of the fine holes 243provided with the silicon oxide layer 244 have been simplified forfacilitating the explanation of the construction of the apparatus.

[0432] The main electrodes 246 a, 246 b, 246 c are provided respectivelyfor the apparatus units 241 a, 241 b, 241 c. As with the main electrode206, each main electrode is provided so as to surround the plurality offine holes 243 (five fine holes in the embodiment shown in the drawing).The main electrodes 246 a, 246 b, 246 c are formed of a conductive thinfilm of aluminum, copper, chromium, gold, silver, silicon or the likeand may be generally provided on the silicon substrate 242 side throughan electrically insulating thin film of polyimide or the like.

[0433] The counter electrode 247 may be in an electrically grounded orfloating state. In order to write finer lines, the grounded state ispreferred. In the embodiment shown in the drawing, the counter electrode247 is in an electrically grounded state and, when a predeterminedvoltage has been applied to the main electrode 246, functions to applyan electric field to the fine holes 243. As with the counter electrode207 in the apparatus 201 for fine pattern formation, the counterelectrode 247 may be in various forms according to need.

[0434] The support member 248 is provided on the surface 242A side ofthe silicon substrate 242, for supporting the silicon substrate 242. Inthe embodiment shown in the drawing, as with the support member 208described above, the support member 248 comprises: a base 248 a, which,as with the silicon substrate 242, is flat; a flange portion 248 bprovided on the periphery of the base 248 a; and an opening 248 cprovided at the center of the base 248 a. The support member 248 isfixed to the surface 242A side of the silicon substrate 242 by theflange portion 248 b. This can provide a space for supplying ink to aportion between the silicon substrate 242 and each of the supportmembers 248 (ink supply space). The fixation of the support member 248to the silicon substrate 242 through heat-resistant glass (not shown),can improve the working efficiency of later steps in the production ofthe apparatus for fine pattern formation. As with the support member 208described above, this support member 248 is preferably formed of amaterial having a coefficient of linear expansion in the range ofone-tenth of the coefficient of linear expansion of the siliconsubstrate 242 to 10 times the coefficient of linear expansion of thesilicon substrate 242.

[0435] The ink passages 249 are connected to the openings 248 c of therespective support members 248, and the other ends of the ink passages249 are connected respectively to ink supplying devices 250 a, 250 b,250 c. The ink supplying devices 250 a, 250 b, 250 c may be properlyselected from a continuous supply pump, a constant rate supply pump andthe like according to applications of the apparatus 241 for fine patternformation. In the embodiment shown in the drawing, only one ink passage249 is provided in each support member 248. In this case, a constructionmay also be adopted wherein a plurality of openings 248 c, the number ofwhich is determined by taking into consideration, for example, theevenness of ink flow pressure, are provided for one support member 248,and the ink passage 249 is connected to each opening 248 c. The inkpassage may be provided within the support member 248.

[0436] In the above apparatus 241 for fine pattern formation accordingto the present invention, since a combination of an electric field,formed between the main electrodes 246 a, 246 b, 246 c and the counterelectrode 247, with the pressure of ink for supply from the inksupplying devices 250 a, 250 b, 250 c is used as ink ejection means, inkcan be ejected in a very small amount at low ink supply pressure withhigh accuracy through the fine holes 243 of the silicon substrate 242.When ink is present in the ink supply space, the formation of theelectric field suffices for the ejection of the ink and, in this case,ink supply pressure is not required. When different inks are suppliedrespectively from the ink supplying devices 250 a, 250 b, 250 c, apattern may be directly written with a desired ink for each of theapparatus units 241 a, 241 b, 241 c. This is particularly advantageousfor the formation of a stripe pattern by the method for patternformation according to the present invention which will be describedlater. The width and amount of ink ejected from the fine holes 243 canbe regulated by varying the strength of field formed between the mainelectrodes 246 a, 246 b, 246 c and the counter electrode 247. Therefore,ink can be ejected through the fine holes 243 having a predeterminedopening diameter in desired ejection width and ejection amount. Further,the amount of ink ejected can be set as desired by varying the amount ofink supplied. The width and amount of ink ejected through the fine holes243 can be regulated by varying both the field strength and the inksupply pressure. Furthermore, in the apparatus 241 for fine patternformation, since the apparatus units 241 a, 241 b, 241 c are providedintegrally with one another, there is no need to join a plurality ofapparatuses to one another and, in addition, the positional accuracy ofthe apparatuses is very high. Furthermore, the amount of ink ejected maybe set as desired by controlling the ink supplying devices 250 a, 250 b,250 c to vary the amount of ink supplied.

[0437] Also in the apparatus 241 for fine pattern formation, the nozzlesas shown in FIG. 50 may be provided so as to be protruded from theopenings 243 b of the fine holes 243 on the back surface 242B side ofthe silicon substrate 242. In this case, a reinforcing layer like thereinforcing layer 215′ may be formed on the nozzles.

[0438] Further, also in the apparatus 241 for fine pattern formation,the openings 243 a on the surface 242A side of the fine holes 243 may bein a tapered concave form or a multistaged concave form as describedabove. This can reduce the passage resistance of ink and can realize theejection of a higher-viscosity ink through the plurality of fine holes243 in a very small amount with high accuracy.

Sixth Embodiment

[0439]FIG. 57 is a diagram showing a further embodiment of the apparatusfor fine pattern formation according to the present invention, whereinFIG. 57 (A) is a schematic cross-sectional view and FIG. 57 (B) a bottomview. In FIG. 57, an apparatus 251 for fine pattern formation comprises:a silicon substrate 252; three main electrodes 256 a, 256 b, 246 c whichare electrically independently of one another and are provided on thesurface 252A side of the silicon substrate 252; a support member 258; acounter electrode 257 provided on the back surface 252B side of thesilicon substrate 252 while leaving a predetermined space between themain electrodes and the counter electrode; three ink passages 259 a, 259b, 259 c provided within the silicon substrate 252 and within thesupport member 258; and ink supplying devices 260 a, 260 b, 260 cconnected respectively to the ink passages.

[0440] The silicon substrate 252 is provided with a plurality of fineholes 253 which extend through the silicon substrate 252 from thesurface 252A side of the silicon substrate 252 to the back surface 252Bside of the silicon substrate 252, and openings 253 a on the surface252A side of the fine holes 253 each are exposed within any one of thethree ink passages 259 a, 259 b, 259 c provided in a groove form on thesurface 252A side. The silicon substrate 252 may be formed of the samematerial as the silicon substrate 202, and the thickness of the siliconsubstrate 252 may also be set in the same range as the silicon substrate202.

[0441] A plurality of fine holes 253 are arranged on an identical linealong a predetermined direction (a direction indicated by an arrow a inFIG. 57 (B)). A plurality of these lines are provided at pitch P. In theembodiment shown in the drawing, six fine hole lines 253A, 253B, 253C,253D, 253E, 253F, in each of which a plurality of fine holes arearranged along a direction indicated by the arrow a, are provided atpitch P. The transverse sectional form, the longitudinal sectional form,the opening diameter, and the pitch of the fine holes 253 may beproperly set in the same manner as in the fine holes 203. The siliconoxide layer 254 provided on the wall surface of the fine holes 253 mayalso be the same as the silicon oxide layer 204. In the embodiment shownin the drawing, for example, the opening diameter, the number, and thepitch of the fine holes 253 provided with the silicon oxide layer 254have been simplified for facilitating the explanation of theconstruction of the apparatus.

[0442] The main electrodes 256 a, 256 b, 256 c are provided so as tosurround the fine hole lines 253A, 253B, 253C, 253D, 253E, 253F.Specifically, the main electrode 256 a surrounds the fine hole lines253A and 253D, the main electrode 256 b surrounds the fine hole lines253B and 253E, and the main electrode 256 c surrounds the fine holelines 253C and 253F. These three main electrodes 256 a, 256 b, 256 c areelectrically independent of one another. These main electrodes 256 a,256 b, 256 c are formed of a conductive thin film of aluminum, copper,chromium, gold, silver, silicon or the like and may generally beprovided on the silicon substrate 252 side through an electricallyinsulating thin film of polyimide or the like. The main electrodes maynot be electrically independent of one another, and a common electrodemay be adopted.

[0443] The counter electrode 257 may be in an electrically grounded orfloating state. In order to write finer lines, the grounded state ispreferred. In the embodiment shown in the drawing, the counter electrode257 is in an electrically grounded state and, when a predeterminedvoltage has been applied to the main electrodes 256 a, 256 b, 256 c, aelectric field occurs between the counter electrode 257 and the mainelectrodes 256 a, 256 b, 256 c. As with the counter electrode 207 in theapparatus 201 for fine pattern formation, the counter electrode 257 maybe in various forms according to need.

[0444] The support member 258 is a plate member which is provided on thesurface 252A side of the silicon substrate 252 to hold the siliconsubstrate 252, and ink passages 259 c are provided in a groove form inthe support member 258 on its silicon substrate 252 side.

[0445]FIG. 58 is a transverse sectional view taken on line A-A of thesilicon substrate 252 shown in FIG. 57 (A), and FIG. 59 a transversesectional view taken on line B-B of the support member 258 shown in FIG.57 (A).

[0446] As shown in FIG. 57 (A) and FIG. 58, in the silicon substrate252, an ink passage 259 a in a groove form is provided so as to connecteach of openings in fine hole lines 253A, 253D to the ink supplyingdevice 260 a, and an ink passage 259 b in a groove form is provided soas to connect each of the openings in fine hole lines 253B, 253E to theink supplying device 260 b. Further, an ink passage 259 c in a grooveform is provided on each of the openings in fine hole lines 253C, 253F.Further, as shown in FIG. 57 (A) and FIG. 59, in the support member 258,the ink passage 259 c in a groove form is provided so as to connect eachof the openings in the fine hole lines 253C, 253F to the ink supplyingdevice 260 c.

[0447] As shown in FIG. 60, three ink passages 259 a, 259 b, 259 cprovided between the support member 258 and the silicon substrate 252are independent of one another. As with the support member 208, thesupport member 258 is preferably formed of a material having acoefficient of linear expansion in the range of one-tenth of thecoefficient of linear expansion of the silicon substrate 252 to 10 timesthe coefficient of linear expansion of the silicon substrate 252.

[0448] The ends of the ink passages 259 a, 259 b, 259 c are connectedrespectively to the ink supplying devices 260 a, 260 b, 260 c. The inksupplying devices 260 a, 260 b, 260 c are not particularly limited, andany of a continuous supply pump, a constant rate supply pump and thelike may be used as the ink supplying device and may be properlyselected according to the application of the apparatus 251 for finepattern formation.

[0449] In the above apparatus 251 for fine pattern formation accordingto the present invention, since a combination of an electric field,formed between the main electrodes 256 a, 256 b, 256 c and the counterelectrode 257, with the pressure of ink for supply from the inksupplying devices 260 a, 260 b, 260 c is used as ink ejection means, inkcan be ejected through the fine holes 253 in the silicon substrate 252in a very small amount at low ink supply pressure with high accuracy.

[0450] When ink is present in the ink supply space, the formation of theelectric field suffices for the ejection of the ink and, in this case,ink supply pressure is not required. The supply of different inksrespectively from the ink supplying devices 260 a, 260 b, 260 c permitsa pattern to be formed by direct writing with a desired ink for eachfine hole line grouped according to the ink passages 259 a, 259 b, 259 c(a group consisting of fine hole lines 253A and 253D, a group consistingof fine hole lines 253B and 253E, and a group consisting of fine holelines 253C and 253F), and is particularly advantageous for the formationof a stripe pattern by the method for pattern formation according to thepresent invention which will be described later. The width and amount ofink ejected through the fine holes 253 can be regulated by varying thestrength of field formed between the main electrodes 256 a, 256 b, 256 cand the counter electrode 257. Therefore, ink can be ejected through thefine holes 253 having a predetermined opening diameter in desired inkejection width and amount.

[0451] Further, the amount of ink ejected can be set as desired bycontrolling the ink supplying devices 260 a, 260 b, 260 c to vary theamount of ink supplied. Furthermore, the width and amount of ink ejectedthrough the fine holes 253 can be regulated by varying both the strengthof field and the ink supply pressure. Furthermore, the apparatus 253 forfine pattern formation does not comprise a plurality of apparatuses forrespective inks which have been joined to each other or one another.Therefore, the positional accuracy of each of the fine hole lines isvery high.

[0452] Also in the apparatus 253 for fine pattern formation, the nozzlesas shown in FIG. 50 may be provided so as to be protruded from theopenings 253 b of the fine holes 253 on the back surface 252B side ofthe silicon substrate 252. In this case, a reinforcing layer like thereinforcing layer 215′ may be formed on the nozzles.

[0453] Further, also in the apparatus 253 for fine pattern formation,the openings 253 a on the surface 252A side of the fine holes 253 may bein a tapered concave form or a multistaged concave form as describedabove. This can reduce the passage resistance of ink and can realize theejection of a higher-viscosity ink through the plurality of fine holes253 in a very small amount with high accuracy.

Seventh Embodiment

[0454]FIG. 61 is a plan view showing a further embodiment of theapparatus for fine pattern formation according to the present invention.In FIG. 61, an apparatus 261 for fine pattern formation comprises: asilicon substrate 262; a main electrode provided on the surface 262Aside of the silicon substrate 262; a support member; a counter electrodeprovided on the back surface side of the silicon substrate 262 whileleaving a predetermined space between the main electrode and the counterelectrode; an ink passage for supplying ink to a space between thesilicon substrate 262 and the support member; and an ink supplyingdevice connected to the ink passage. In FIG. 61, however, only thesilicon substrate 262 is shown, and the main electrode, the counterelectrode, the support member, the ink passage, and the ink supplyingdevice are not shown.

[0455] The silicon substrate 262 has a plurality of fine holes 263 whichextend through the silicon substrate 262 from the surface 262A side ofthe silicon substrate 262 to the back surface side of the siliconsubstrate 262. The fine holes 263 are provided at positions such thatthe fine holes 263 constitute one pattern 265, and a plurality ofpatterns 265 (10 patterns in the embodiment shown in the drawing) areprovided on the silicon substrate 262. In the drawing, the fine holes263 are shown in only one pattern 265, and, for the other patterns 265,only the outline is indicated by a chain line.

[0456] The silicon substrate 262 may be formed of the same material asused in the silicon substrate 202, and the thickness of the siliconsubstrate 262 also may be set in the same range as in the siliconsubstrate 202. The transverse sectional form, the longitudinal sectionalform, the opening diameter, and the pitch of the fine holes 263 may beproperly set in the same manner as in the fine holes 203. The fine holes263 may have a silicon oxide layer on their wall surface, and thissilicon oxide layer also may be the same as the silicon oxide layer 204.

[0457] The main electrode is provided on the surface 262A side of thesilicon substrate 262 so as to surround each pattern 265. In this case,the main electrode surrounding the patterns 265 may be electricallyindependent for each pattern, or alternatively a common electrode may beadopted. The main electrode is formed of a conductive thin film ofaluminum, copper, chromium, gold, silver, silicon or the like and maygenerally be provided on the silicon substrate 262 side through anelectrically insulating thin film of polyimide or the like.

[0458] The counter electrode is in an electrically grounded state andfunctions to apply an electric field to the fine holes 263 upon theapplication of a predetermined voltage to the main electrode. Thecounter electrode may be the same as that adopted in the apparatus 201for fine pattern formation.

[0459] Further, in the silicon substrate 262, a support member having,on its periphery, a flange portion as described above in connection withthe support member 208 may be provided, and the flange portion in thesupport member may be fixed to the peripheral portion (a shaded regionin FIG. 61). The ink supply passage may be connected to the opening ofthe support member, and the ink supplying device may be connected to theother end of the ink supply passage.

[0460] In the above apparatus 261 for fine pattern formation, since acombination of an electric field, formed between the main electrode andthe counter electrode, with an ink supply pressure from the inksupplying device is used as ink ejection means, ink can be ejected in avery small amount with high accuracy at a low ink supply pressurethrough the fine holes 263 in the silicon substrate 262. When ink ispresent in the ink supply space, the formation of the electric fieldsuffices for the ejection of the ink and, in this case, ink supplypressure is not required. A pattern in a form corresponding to thepattern 265 can be stably formed on a pattern object with high accuracyby ejecting ink from the fine holes 263 in the silicon substrate 262 ina suitable amount such that inks ejected from mutually adjacent finenozzles 263 come into contact with each other on the pattern object todirectly write a pattern. The amount of the ink ejected can be regulatedby controlling the ink supplying device.

[0461] In the above embodiment, all the plurality of patterns 265 are inan identical form. However, the present invention is not limited to thisonly. For example, the pattern may be in a desired form, such as aconductor pattern for a printed wiring board.

[0462] Also in the apparatus 261 for fine pattern formation, nozzles asshown in FIG. 50 may be provided in a protruded form on the openings inthe fine holes 263 on the back surface side of the silicon substrate262. In this case, a reinforcing layer like the reinforcing layer 215′may be formed on the nozzles.

[0463] Further, also in the apparatus 261 for fine pattern formation,the openings on the surface 262A side of the fine holes 263 may betapered or multistaged concaves as described above. This can reduce thepassage resistance of ink, and, consequently, an ink having higherviscosity can be ejected through the plurality of fine holes 263 in avery small amount with high accuracy.

[0464] The above-described apparatus for fine pattern formationaccording to the present invention can be applied, for example, to theformation of a black matrix pattern or a color pattern for liquidcrystal displays, the formation of a phosphor layer for plasma displays,and the formation of a pattern in electroluminescence, as well as toconductor pattern formation of printed wiring boards.

[0465] The ink used may be selected by taking into considerationproperties such as electric conductivity and viscosity. For example, theink preferably has an electric conductivity in the range of 1×10⁻¹² S/cmto 1×10⁻⁴ S/ω·cm and a viscosity of 0.3 to 50000 mPa.s (cps).

III-2 Embodiments of Production of Apparatus for Fine Pattern Formation

[0466] Next, an embodiment of the production of the apparatus for finepattern formation according to the present invention will be describedby taking the apparatus 211 for fine pattern formation shown in FIG. 50as an example with reference to FIGS. 62 and 63.

[0467] At the outset, a silicon substrate 212 having a cleaned surfaceis oxidized in a thermal oxidation furnace to form an about 1 to 2μm-thick silicon oxide film 212′ on the whole area of the siliconsubstrate 212 (FIG. 62 (A)). The silicon oxide film 212′ may be formedby wet oxidation.

[0468] Next, a photosensitive resist is coated on one surface of thesilicon substrate 212, and exposure through a predetermined photomaskand development are carried out to form a resist pattern R (Fig. 62(B)). Next, the silicon oxide film 212′ is patterned, for example, withBHF 16 (a 22% aqueous ammonium monohydrodifluoride solution) using thisresist pattern R as a mask (FIG. 62 (C)). This patterning may also becarried out by dry etching using RIE (reactive ion etching) (processgas: CHF₃). In this patterning, the silicon oxide film 212′ in its site,on which the resist pattern R has not been provided, is removed.

[0469] Next, fine holes 213 are formed in the silicon substrate 212 to adesired depth using the patterned silicon oxide film 212′ as a mask(FIG. 62 (D)). The fine holes 213 may be formed, for example, by highaspect etching, such as dry deep etching, for example, by ICP-RIE(inductively coupled plasma-reactive ion etching), or wet etching, FIBprocessing, laser processing, or electric discharge machining. The fineholes 213 are formed to a predetermined depth such that the holes do notyet completely pass through the silicon substrate 212.

[0470] Next, the resist pattern R and the silicon oxide film 212′ areremoved, and oxidation is again carried out in a thermal oxidationfurnace to form an about 5000 to 10000 angstrom-thick silicon oxidelayer 214 on the whole area of the silicon substrate 212 (FIG. 62 (E)).

[0471] Next, a main electrode 216 is formed on the surface 212A side ofthe silicon substrate 212 so as to surround the fine holes 213. The mainelectrode may be formed, for example, by a method a metallic foil havinga predetermined shape is fixed through a polyimide resin, by a methodwherein a multilayered film of an insulating thin film/metallic thinfilm is formed by a vacuum process, such as sputtering and thenpatterned by photolithography, or a method wherein a multilayered filmis formed by a vacuum process through a metallic mask, a silicon mask orthe like having a desired opening pattern. Thereafter, the supportmember 218 in its flange portion 218 b is fixed onto the peripheralportion on the surface side (on the fine hole formed side) of thesilicon substrate 212 (FIG. 63 (A)). This fixation may be carried out,for example, by anodic bonding or epoxy adhesive.

[0472] Next, only the outer surface side of the silicon substrate 212 isimmersed in BHF 16 to remove the silicon oxide layer 214 in this siteand thus to expose the back surface of the silicon substrate 212.Thereafter, etching is carried out with TMAH (tetramethylammoniumhydroxide) from the back surface side of the silicon substrate 212 (FIG.63 (B)). In this etching, since the silicon oxide layer 214 provided onthe inner wall of the fine holes 213 is resistant to TMAH, fine tubesformed of the silicon oxide layer 214 are protruded on the siliconsubstrate 212 side.

[0473] Next, the front end of the fine tubes formed of the silicon oxidelayer 214 is dissolved and removed with BHF 16 to form openings (FIG. 63(C)). Thereafter, the back surface side of the silicon substrate 212 isagain etched with TMAH. When nozzles 215 formed of the silicon oxidelayer 214 having a predetermined length have been formed, etching withTMAH is completed (FIG. 63 (D)). An ink supplying device is thenconnected to the opening 218 c of the support member 218 through the inkpassage, and a counter electrode 217 is then disposed on the backsurface side of the silicon substrate 212 while leaving a predeterminedspace between the main electrode and the counter electrode. Thus, theapparatus 211 for fine pattern formation according to the presentinvention as shown in FIG. 50 can be prepared.

[0474] Besides etching with TMAH, dry process by RIE (reactive ionetching) may also be used for the etching of the back surface side ofthe silicon substrate 212.

[0475] Further, in the above embodiment, a silicon oxide film 212′ isformed. Instead of the silicon oxide film, a thin film of aluminum maybe formed by sputtering or the like for the preparation of the apparatusfor fine pattern formation. In this case, in the above step ofpatterning (FIG. 62 (C)), an aluminum etchant (mixed acid aluminum) maybe used.

[0476] The apparatus 201 for fine pattern formation as shown in FIG. 48may be produced by forming fine holes 213 so as to pass through thesilicon substrate 212 by a process corresponding to FIG. 62 (D), or bydissolving and removing protruded fine tubes formed of a silicon oxidelayer 214 with hydrofluoric acid by a process corresponding to FIG. 63(C).

[0477] Another embodiment of the production of the apparatus for finepattern formation according to the present invention will be describedby taking the apparatus 221 for fine pattern formation shown in FIG. 53as an example with reference to FIGS. 64 and 65.

[0478] At the outset, the surface of a silicon substrate 222 having<100> crystallographic orientation is cleaned, and an about 200 to 3000angstrom-thick silicon nitride (Si₃N₄) layer 222′ is formed on the wholearea of the silicon substrate 222.

[0479] A photosensitive resist is then coated on the silicon nitridelayer 222′ in its portion located on the surface 222A side of thesilicon substrate 222, and exposure through a predetermined photomaskand development are carried out to form a resist pattern R.Subsequently, the silicon nitride layer 222′ is etched by RIE (reactiveion etching (process gas: CF₄ or SF₆)) using the resist pattern R as amask to form a pattern having openings 222′a for taper (FIG. 64 (A)).The silicon nitride layer 222′ may be formed, for example, by lowpressure CVD. The depth, opening diameter, and shape of tapered concaves223′a, which will be described later, are determined by the size andshape of the openings 222′a for taper in the silicon nitride layer 222′.In general, the size of the opening for taper is preferably set in therange of 10 to 200 μm. The shape of the opening for taper may beproperly selected from square, circle and the like.

[0480] Next, the silicon substrate 222 is subjected tocrystallographically anisotropic etching with an aqueous potassiumhydroxide solution using the silicon nitride layer 222′ as a mask. Inthis etching, the silicon substrate 222 in its portions exposed to theopenings 222′a for taper is etched in the direction of depth so that<111> crystallographic orientation appears. This etching is preferablycarried out, for example, until the apex of inverted quadrangularpyramid tapered openings is closed (i.e., until inverted quadrangularpyramid concaves are completely formed). As a result, tapered concaves223′a are formed on the surface 222A side of the silicon substrate 222(FIG. 64 (B)).

[0481] Next, the resist pattern R is removed, and a mask thin film 222″is formed on the surface 222A side and the back surface 222B side of thesilicon substrate 222. The mask thin film 222″ on the back surface 222Bside of the silicon substrate 222 remote from the tapered concaves 223′ais then patterned to form fine openings 222″a (FIG. 64 (C)). This fineopening 222″a is formed so that the center of the opening substantiallyconforms to the center (apex) of the tapered concave 223′a through thesilicon substrate 222. The diameter of openings in fine holes 223 andfine nozzles 225, which will be described later, is determined by thesize of the fine openings 222″a. In general, the size of the fineopenings 222″a is preferably set in the range of 1 to 100 μm.

[0482] In addition to a metallic thin film, a resist, a thin film ofsilicon oxide or a combination of both the materials (resist/thin filmof silicon oxide) may be used as the mask thin film. Metallic thin filmsinclude thin films of aluminum, nickel, chromium and the like, and,preferably, the metallic thin film is formed to a thickness of about1000 to 2000 angstroms, for example, by sputtering or vacuum vapordeposition. For example, when aluminum is used as the metallic thinfilm, an aluminum etchant (mixed acid aluminum) may be used in theetching. Further, when the resist is formed as the mask thin film, spincoating may be used. In the case of silicon oxide, the thin film can beformed by sputtering or low pressure CVD.

[0483] Next, through fine holes 223 are formed in the silicon substrate222 by deep etching using the mask thin film 222″ as a mask from theback surface 222B side of the silicon substrate 222 (FIG. 64 (D)). Theformation of the through fine holes 223 may be carried out, for example,by a high aspect etching technique, such as dry etching or deep etching,for example, by an ICP-RIE (inductively coupled plasma-reactive ionetching). In this deep etching, as soon as the through fine holes 223extended to the interior of the tapered concaves 223′a, the mask thinfilm 222″ (mask thin film 222″ within the tapered concaves 223′a) formedon the surface 222A side of the silicon substrate 222 functions as astopping layer. This can eliminate the need to control the depth of thefine holes 223 formed and can render the process simple. Further, inparticular, dry etching by ICP-RIE can significantly shorten the timenecessary for the formation of the through fine holes 223.

[0484] Next, the mask thin film 222″ is removed, and oxidation iscarried out in a thermal oxidation furnace to form an about 5000 to10000 angstrom-thick silicon oxide layer 224 on the wall surface of thethrough fine holes 223 and on the wall surface of the tapered concaves223′a (FIG. 65 (A)).

[0485] Next, the silicon nitride layer 222′ is removed, and dry etchingis carried out from the back surface 222B side of the silicon substrate222 remote from the tapered concaves 223′a. In this dry etching, a partof the silicon substrate 222 is etched to expose the silicon oxide layer224 formed on the inner wall of the through fine holes 223. When thissilicon oxide layer 224 has been exposed by a desired length, the dryetching is stopped to prepare nozzles 225 formed of silicon oxideprotruded on the etching side of the silicon substrate 222 (FIG. 65(B)).

[0486] Although the Bosch process utilizing an ICP-RIE device has beenused in the above high aspect etching, the etching method is not limitedto this only.

[0487] Next, a main electrode 226 is formed on the surface 222A side ofthe silicon substrate 222 so as to surround the tapered concaves 223′a.The main electrode may be formed, for example, by a method wherein ametallic foil having a predetermined shape is fixed through a polyimideresin, by a method wherein a multilayered film of an insulating thinfilm/metallic thin film is formed by a vacuum process, such assputtering and then patterned by photolithography, or a method wherein amultilayered film is formed by a vacuum process through a metallic mask,a silicon mask or the like having a desired opening pattern.

[0488] Subsequently, the support member 228 in its flange portion 228 bis fixed onto the peripheral portion on the surface side (on the finehole formed side) of the silicon substrate 222 (FIG. 65 (C)). Thisfixation may be carried out, for example, by anodic bonding or epoxyadhesive. Thereafter, an ink supplying device is connected to theopening 228 c of the support member 228 through the ink passage, and acounter electrode 227 is then disposed on the back surface side of thesilicon substrate 222 while leaving a predetermined space between themain electrode and the counter electrode. Thus, the apparatus 221 forfine pattern formation according to the present invention as shown inFIG. 53 can be prepared.

[0489] A further embodiment of the production of the apparatus for finepattern formation according to the present invention will be describedby taking the apparatus 231 for fine pattern formation shown in FIG. 54as an example with reference to FIGS. 66 and 67.

[0490] At the outset, an about 200 to 3000 angstrom-thick siliconnitride (Si₃N₄) layer 232′ is formed on the whole area of the siliconsubstrate 232 having a cleaned surface. Next, a mask thin film 232″ isformed on both surfaces of the silicon nitride layer 232′, and the maskthin film 232″ in its portion located on the surface 232A side of thesilicon substrate 232 is patterned to form a mask pattern having wideopenings 232″a. The mask thin film 232″ in its portion located on theback surface 232B side of the silicon substrate 232 is patterned to forma mask pattern having fine openings 232″b (FIG. 66 (A)). The center ofthe wide opening 232″a is set so as to substantially conform to thecenter of the fine opening 232″b through the silicon substrate 232.

[0491] The opening diameter of multistaged wide concaves 233′a, whichwill be described later, is determined by the size and shape of the wideopening 232″a. In general, the size of the wide opening is preferablyset in the range of 5 to 200 μm. Further, the diameter of openings infine holes 233 and fine nozzles 235, which will be described later, isdetermined by the size of the fine openings 232″b. In general, the sizeof the fine openings is preferably set in the range of 1 to 100 μm.

[0492] The silicon nitride layer 232′ may be formed in the same manneras used in the formation of the silicon nitride layer 222′.

[0493] In addition to a metallic thin film, a resist, a thin film ofsilicon oxide or a combination of both the materials (resist/thin filmof silicon oxide) may be used as the mask thin film. Metallic thin filmsinclude thin films of aluminum, nickel, chromium and the like, and,preferably, the metallic thin film is formed to a thickness of about1000 to 2000 angstroms, for example, by sputtering or vacuum vapordeposition. For example, when aluminum is used as the metallic thinfilm, an aluminum etchant (mixed acid aluminum) may be used in theetching. Further, when the resist is formed as the mask thin film, spincoating may be used. In the case of silicon oxide, the thin film can beformed by sputtering or low pressure CVD.

[0494] Fine holes 233 are then formed by deep etching using the maskpattern having the fine openings 232″b as a mask from the back surface232B side of the silicon substrate 232 (FIG. 66 (B)). The fine holes 233may be formed, for example, by a high aspect etching technique, such asa Bosch process using an ICP-RIE (inductively coupled plasma-reactiveion etching) device. The formation of the fine holes 233 is continueduntil the depth reaches a predetermined level such that the fine holes233 do not yet completely pass through the silicon substrate 232. In thepresent invention, in order to facilitate the regulation of the depth ofthe fine holes 233, an SOI (silicon on insulator) wafer may be used asthe silicon substrate 232. The SOI wafer has a multilayer structurecomprising a silicon oxide thin film sandwiched between single crystalsilicons. The silicon oxide thin film functions as a stopping layer inthe deep etching. This can eliminate the need to control the depth inthe formation of the fine holes 233. When an SOI wafer having amultilayer structure, in which two silicon oxide thin films aresandwiched between single crystal silicons, is used, multistagedopenings, of which the number of stages is larger, can be formed.

[0495] Next, wide concaves 233′a are formed from the surface 232A sideof the silicon substrate 232 by deep etching using the mask patternhaving wide openings 232″a as a mask (FIG. 66 (C)). The wide concaves233′a can be formed, for example, by a high aspect etching technique,such as a Bosch process using an ICP-RIE (inductively coupledplasma-reactive ion etching) device. The formation of the wide concaves233′a is continued until the openings of the fine holes 233 appearwithin the wide concaves 233′a.

[0496] Next, the mask thin film 232″ is removed, and oxidation iscarried out in a thermal oxidation furnace to form an about 5000 to10000 angstrom-thick silicon oxide layer 234 on the wall surface of thefine holes 233 and on the wall surface of the wide concaves 233′a (FIG.67 (A)).

[0497] Next, the silicon nitride layer 232′ is removed, and dry etchingis carried out from the back surface 232B side of the silicon substrate232 remote from the wide concaves 233′. In this dry etching, a part ofthe silicon substrate 232 is etched to expose the silicon oxide layer234 formed on the inner wall of the through fine holes 233. When thissilicon oxide layer 234 has been exposed by a desired length, the dryetching is stopped to prepare nozzles 235 formed of silicon oxideprotruded on the etching side of the silicon substrate 232 (FIG. 67(B)).

[0498] Although the Bosch process utilizing an ICP-RIE device has beenused in the above high aspect etching, the etching method is not limitedto this only.

[0499] Next, a main electrode 236 is formed on the surface 232A side ofthe silicon substrate 232 so as to surround the concaves 233′a. The mainelectrode may be formed, for example, by a method wherein a metallicfoil having a predetermined shape is fixed through a polyimide resin, bya method wherein a multilayered film of an insulating thin film/metallicthin film is formed by a vacuum process, such as sputtering and thenpatterned by photolithography, or a method wherein a multilayered filmis formed by a vacuum process through a metallic mask, a silicon mask orthe like having a desired opening pattern.

[0500] Thereafter, the support member 238 in its flange portion 238 b isfixed onto the peripheral portion on the surface side (on the fine holeformed side) of the silicon substrate 232 (FIG. 67 (C)). This fixationmay be carried out, for example, by anodic bonding or epoxy adhesive.Thereafter, an ink supplying device is then connected to the opening 238c of the support member 238 through the ink passage, and a counterelectrode 237 is then disposed on the back surface side of the siliconsubstrate 232 while leaving a predetermined space between the mainelectrode and the counter electrode. Thus, the apparatus 231 for finepattern formation according to the present invention as shown in FIG. 54can be prepared.

III-3 Method for Fine Pattern Formation First Embodiment

[0501]FIG. 68 is a diagram illustrating one embodiment of the method forfine pattern formation according to the present invention using theapparatus 241 for fine pattern formation according to the presentinvention. In FIG. 68, while supplying ink A, ink B, and ink Crespectively from the ink supplying devices 250 a, 250 b, 250 c throughthe ink passages 249, in such as state that a predetermined voltage hasbeen applied to the main electrodes 246 a, 246 b, 246 c in the apparatus241 for fine pattern formation according to the present invention, apattern object S is scanned relative to the apparatus 241 for finepattern formation in a predetermined direction (a direction indicated byan arrow A). The scanning direction A is identical to the arrangementdirection A (see FIG. 56) of the fine holes in the apparatus 241 forfine pattern formation. In this case, the space between the siliconsubstrate 242 in the apparatus 241 for fine pattern formation and thepattern object S may be set in the range of about 50 to 500 μm.

[0502] In the embodiment shown in the drawing, the pattern object S atleast in its surface is electrically conductive and serves also as agrounded counter electrode 247. A thin electrical insulator, such aspaper or films, may also be used as a pattern object. In this case, forexample, a substrate for mounting thereon the thin electrical insulatoris used as a grounded counter electrode 247. The counter electrode 247may be in an electrically grounded or floating state. In order to writefiner lines, however, the grounded state is preferred.

[0503] According to this construction, inks ejected from the fine holes243 in the silicon substrate 242 form, by direct writing, a stripepattern comprising ink A, ink B, and ink C which have been repeatedlysequenced in that order on the pattern object S. In this case, the pitchof the stripes is P2. In this stripe pattern, since one stripe is formedof ink ejected from the plurality of fine holes on an identical line,even when the amount of ink ejected from the individual fine holes issmall, the scanning speed of the pattern object S can be increased toincrease the pattern formation speed. This stripe pattern is formed withvery high accuracy by varying the diameter of the fine holes 243 orvarying the strength of field formed between the main electrodes 246 a,246 b 246 c and the counter electrode 247 to regulate the ejection widthof ink ejected through the fine holes 243, and the process is simplerthan the conventional photolithography.

[0504] When the pattern object S is flexible, preferably, a back-uproller is disposed on the back surface of the pattern object S so as toface the apparatus 241 for fine pattern formation. In this case, thepattern object S is carried while applying tension to the pattern objectS by the back-up roller to directly write a pattern on the patternobject S.

[0505] Further, in the method for fine pattern formation according tothe present invention, a fine pattern may be formed by transferring apattern, written on the counter electrode 247 by the above method, ontoanother pattern object.

Second Embodiment

[0506]FIG. 69 is a diagram illustrating a further embodiment of themethod for fine pattern formation according to the present invention,wherein the apparatus 261 for fine pattern formation according to thepresent invention has been used. In FIG. 69, an apparatus 261 for finepattern formation (in the embodiment shown in the drawing, only thesilicon substrate 262 is shown) is disposed on a predetermined positionof the pattern object S, and, while applying a predetermined voltage tothe main electrode, a given amount of ink supplied from the ink passageis ejected through the fine holes 263 onto the pattern object to form apattern. In the embodiment shown in the drawing, the pattern object S atleast in its surface is electrically conductive and serves also as agrounded counter electrode. A thin electrical insulator, such as paperor films, may also be used as a pattern object S. In this case, forexample, a substrate for mounting thereon the thin electrical insulatoris used as a grounded counter electrode. The counter electrode may be inan electrically grounded or floating state. In order to write finerlines, however, the grounded state is preferred.

[0507] Thereafter, the pattern object S is carried by a predetermineddistance in a direction indicated by an arrow A, and the same patternformation as described above is carried out. A desired pattern 265 canbe formed on the pattern object S by repeating the above procedure. Thespace between the silicon substrate 262 in the apparatus 261 for finepattern formation and the pattern object S may be set in the range ofabout 50 to 500 μm.

[0508] Further, a printed wiring board can be simply produced withoutreplying on photolithography, for example, by forming the pattern 265,formed of the plurality of fine holes 263 in the apparatus 261 for finepattern formation, as a conductor pattern of a printed wiring board, andusing a conductor paste as ink. In this case, a method may be adoptedwherein an electrode in the frame form shown in FIGS. 49 and 51 is usedas the main electrode and a printed wiring board is placed below thecounter electrode followed by pattern formation.

[0509] In the method for fine pattern formation according to the presentinvention, a fine pattern may be formed by transferring a pattern,written on the counter electrode by the above method, onto anotherpattern object.

EXAMPLES

[0510] Next, the following examples further illustrate the presentinvention.

Example I-1 Production of Fine Nozzles

[0511] A silicon substrate having an RCA cleaned surface (diameter 3in., thickness 200 μm, one side polished, crystallographic orientation<100>, coefficient of linear expansion=2.6×10⁻⁶/K) was provided. Asilicon nitride layer was formed on the whole area of this siliconsubstrate by low pressure CVD to a thickness of 0.1 μm. Thereafter, a0.2 μm-thick thin film of aluminum was sputtered on the silicon nitridelayer located on one side of the silicon substrate.

[0512] Next, a photosensitive resist (Micro Posit S 1818, manufacturedby Shipley) was coated on the thin film of aluminum, followed byexposure through a predetermined photomask and development to form aresist pattern. Thereafter, the thin film of aluminum was etched with analuminum etchant (mixed acid aluminum) using the resist pattern as amask, and the resist pattern was then removed to form a metal pattern inwhich 42 fine openings (circular openings having a diameter of 20 μm)are formed on an identical straight line at a pitch of 120 μm (firststep).

[0513] Next, the silicon substrate was deeply etched by ICP-RIE(inductively coupled plasma-reactive ion etching) using the metalpattern as a mask to form through fine holes (diameter 20 μm) in thesilicon substrate (second step).

[0514] Next, the metal pattern was separated and removed with sulfuricacid-aqueous hydrogen peroxide (sulfuric acid: aqueous hydrogenperoxide=1:1), and the silicon substrate was oxidized within a thermaloxidation furnace under the following conditions to form an about 5000to 10000 angstrom-thick silicon oxide layer on the wall surface of thethrough fine holes (third step).

[0515] (Conditions for thermal oxidation)

[0516] Heating temperature: 1050° C.

[0517] Hydrogen gas feed rate: 1 slm

[0518] Oxygen gas feed rate: 1 slm

[0519] Heating time: about 15 hr

[0520] Next, dry etching by ICP-RIE (inductively coupled plasma-reactiveion etching) was carried out from the silicon substrate on its surfacewhere the metal pattern had been provided, thereby removing the siliconnitride layer. Further, the silicon substrate was etched, and the dryetching was stopped when the silicon oxide layer provided on the innerwall of the through fine holes was exposed by a length of 100 μm (fourthstep).

[0521] Thus, fine nozzles formed of silicon oxide in communication withthe fine holes of the silicon substrate were formed by the above stepson the etching side of the silicon substrate. The fine nozzles had anopening diameter of the front end portion of 19 μm in a variation within±1 μm and were formed at a pitch of 120 μm with very high accuracy.

Measurement of Strength of Fine Nozzles

[0522] The silicon substrate was placed horizontally so that the axialdirection of the fine nozzles was vertical. A universal bond testerPC-2400 manufactured by Dage was provided, and a shear testing load cellwas disposed while keeping a distance of about 5 μm between the frontend of the cell and the surface of the silicon substrate and wascollided against three fine nozzles at the same time in the horizontaldirection at a speed of 6 mm/min to break the fine nozzles. The strengthat that time was measured and was found to be 0.16 g per nozzle.

Production of Apparatus for Fine Pattern Formation

[0523] Next, a support member of a polyether ether ketone resin, inwhich a flange portion and an opening had been formed, was fixed withthe aid of an epoxy adhesive onto the silicon nitride layer on theperipheral portion of the surface of the silicon substrate (surfaceremote from the fine nozzles).

[0524] Next, an ink passage formed of a resin pipe was connected to theopening of the support member, and the other end of the resin pipe wasconnected to an ink supplying device (1500 XL, manufactured by EFD).Thus, an apparatus for fine pattern formation according to the presentinvention was prepared.

Formation of Fine Pattern

[0525] The ink supplying device was loaded with ink (Color MosaicCR-7001, manufactured by Fuji Film Olin Co., Ltd.). This ink had aviscosity of 20 mPa.s. Further, a glass substrate (100 mm×100 mm) wasprovided as a pattern object.

[0526] Next, while scanning the glass substrate at a constant speed of50 mm/sec in a direction in which the fine nozzles of the apparatus forfine pattern formation were arranged, ink was supplied from the inksupplying device to the silicon substrate, and ink was ejected throughthe fine nozzles to write a stripe pattern which was then dried. Thestripes constituting the pattern had a line width of 25±1 μm and a linepitch of 25 ±1 μm, that is, were formed with very high accuracy.

Example I-2 Production of Fine Nozzles

[0527] A silicon substrate having an RCA cleaned surface (diameter 3in., thickness 200 μm, one side polished, crystallographic orientation<100>, coefficient of linear expansion=2.6×10⁻⁶/K) was provided. Asilicon nitride layer was formed on the whole area of this siliconsubstrate by low pressure CVD to a thickness of 0.1 μm.

[0528] Next, a photosensitive resist (Micro Posit S 1818, manufacturedby Shipley) was coated on the silicon nitride layer, followed byexposure through a predetermined photomask and development to form aresist pattern. Thereafter, dry etching by RIE (reactive ion etching)was carried out using this resist pattern as a mask to form a pattern inwhich 42 small openings (circular openings having a diameter of 30 μm)were formed on an identical straight line at a pitch of 120 μm (firststep).

[0529] Next, a 0.2 μm-thick thin film of aluminum was sputtered on thesilicon nitride layer pattern. A photosensitive resist (Micro Posit S1818, manufactured by Shipley) was coated on the thin film of aluminum,followed by exposure through a predetermined photomask and developmentto form a resist pattern. Thereafter, the thin film of aluminum wasetched with an aluminum etchant (mixed acid aluminum) using this resistpattern as a mask, and the resist pattern was then removed to form ametal pattern in which fine openings (circular openings having adiameter of 20 μm) are located in the center of the respective smallopenings (second step).

[0530] Next, the silicon substrate was deeply etched by ICP-RIE(inductively coupled plasma-reactive ion etching) using the metalpattern as a mask to form through fine holes (diameter 20 μm) in thesilicon substrate (third step).

[0531] Next, the metal pattern was separated and removed with sulfuricacid-aqueous hydrogen peroxide (sulfuric acid: aqueous hydrogenperoxide=1:1), and the silicon substrate was oxidized within a thermaloxidation furnace under the following conditions to form an about 5000to 10000 angstrom-thick silicon oxide layer on the wall surface of thethrough fine holes and on the silicon substrate in its portions exposedwithin the small openings of the silicon nitride layer pattern (fourthstep).

[0532] (Conditions for thermal oxidation)

[0533] Heating temperature: 1100° C.

[0534] Oxygen gas feed rate: 1 L/min

[0535] Heating time: about 5 hr

[0536] Next, dry etching by ICP-RIE (inductively coupled plasma-reactiveion etching) was carried out from the silicon substrate on its surfacewhere the small openings of the silicon nitride layer pattern had beenformed. In this dry etching, the silicon oxide layer functioned as amask to form nozzle bases integrally with the silicon substrate, and thedry etching was stopped when the length of the nozzle bases reached 100μm (fifth step).

[0537] Thus, fine nozzles comprising nozzle bases, an inner surfacelayer of silicon oxide in communication with the fine holes in thesilicon substrate, and an end face layer of silicon oxide formed on thefront end face of the nozzle bases were prepared by the above steps onthe etching side of the silicon substrate. The fine nozzles had anopening diameter of the front end portion of 20 μm in a variation within±1 μm and were formed at a pitch of 120 μm with very high accuracy. Thewall thickness (5 μm) of the nozzle bases was provided as a differencein radius between the small openings and the fine openings.

Measurement of Strength of Fine Nozzles

[0538] The strength of the fine nozzles was measured in the same manneras in Example 1 and was found to be 0.68 g per nozzle. From this resultand the result obtained in Example 1, it was confirmed that theprovision of nozzle bases in the fine nozzles could contributed to asignificant improvement in strength (about 4.3 times).

Production of Apparatus for Fine Pattern Formation

[0539] Next, a support member of a polyether ether ketone resin, inwhich a flange portion and an opening had been formed, was fixed withthe aid of an epoxy adhesive on the peripheral portion of the surface ofthe silicon substrate (surface remote from the fine nozzles).

[0540] Next, an ink passage formed of a resin pipe was connected to theopening of the support member, and the other end of the resin pipe wasconnected to an ink supplying device (1500 XL, manufactured by EFD).Thus, an apparatus for fine pattern formation according to the presentinvention was prepared.

Formation of Fine Pattern

[0541] The ink supplying device was loaded with ink (Color MosaicCR-7001, manufactured by Fuji Film Olin Co., Ltd.). This ink had aviscosity of 20 mPa.s. Further, a glass substrate (100 mm×100 mm) wasprovided as a pattern object.

[0542] Next, while scanning the glass substrate at a constant speed of50 mm/sec in a direction in which the fine nozzles of the apparatus forfine pattern formation were arranged, ink was supplied from the inksupplying device to the silicon substrate, and ink was ejected throughthe fine nozzles to write a stripe pattern which was then dried. Thestripes constituting the pattern had a line width of 25±1 μm and a linepitch of 25±1 μm, that is, were formed with very high accuracy.

Example I-3 Production of Fine Nozzles

[0543] A silicon substrate having an RCA cleaned surface (diameter 3in., thickness 200 μm, one side polished, crystallographic orientation<100>, coefficient of linear expansion=2.6×10⁻⁶/K) was provided. Asilicon nitride layer was formed on the whole area of this siliconsubstrate by low pressure CVD to a thickness of 0.1 μm.

[0544] Next, a photosensitive resist (Micro Posit S 1818, manufacturedby Shipley) was coated on the silicon nitride layer, followed byexposure through a predetermined photomask and development to form aresist pattern. Thereafter, dry etching by RIE (reactive ion etching)was carried out using this resist pattern as a mask to form a pattern inwhich 42 openings for taper (square openings having a one side length of70 μm) were formed on an identical straight line at a pitch of 120 μm.Further, a photosensitive resist was coated on the silicon nitride layerlocated on the back surface of the silicon substrate, for use as a maskfor subsequent crystal anisotropic etching (first step).

[0545] Next, the surface of the silicon substrate was subjected tocrystal anisotropic etching using the silicon nitride layer as a mask.This etching was carried out by immersing the substrate in a 33 vol %aqueous potassium hydroxide solution kept at 70 to 80° C. for about 50min. As a result, inverted quadrangular pyramid concaves, which had adepth of 50 μm and had an angle of one side to the surface of thesilicon substrate of 55 degrees, were formed in the silicon substrate inits portions exposed to openings for taper (second step).

[0546] Next, a 0.2 μm-thick thin film of aluminum was sputtered on bothsurfaces of the silicon substrate. A photosensitive resist (Micro PositS 1818, manufactured by Shipley) was then coated on the thin film ofaluminum in its portion located on the surface remote from the invertedquadrangular pyramid concaves, followed by exposure through apredetermined photomask and development to form a resist pattern.Thereafter, the thin film of aluminum was etched with an aluminumetchant (mixed acid aluminum) using this resist pattern as a mask, andthe resist pattern was then removed to form a metal pattern in which 42fine openings (circular openings having a diameter of 20 μm) were formedon an identical straight line at a pitch of 120 μm. In this case, themetal pattern was formed in such a manner that the center of the fineopening conformed to the center of the opening in the invertedquadrangular pyramid concave (the apex of the taper) through the siliconsubstrate (third step).

[0547] Next, the silicon substrate was deeply etched by ICP-RIE(inductively coupled plasma-reactive ion etching) using the metalpattern as a mask to form through fine holes (diameter 20 μm) in thesilicon substrate. In this deep etching, the thin film of aluminumformed within the inverted quadrangular pyramid concaves functioned as astopping layer (fourth step).

[0548] Next, the metal pattern was separated and removed with sulfuricacid-aqueous hydrogen peroxide (sulfuric acid: aqueous hydrogenperoxide=1:1), and the silicon substrate was oxidized within a thermaloxidation furnace under the following conditions to form an about 5000to 10000 angstrom-thick silicon oxide layer on the wall surface of theinverted quadrangular pyramid concaves and on the wall surface of thethrough fine holes (fifth step).

[0549] (Conditions for thermal oxidation)

[0550] Heating temperature: 1100° C.

[0551] Oxygen gas feed rate: 1 L/min

[0552] Heating time: about 5 hr

[0553] Next, dry etching by ICP-RIE (inductively coupled plasma-reactiveion etching) was carried out from the silicon substrate on its surfaceside remote from the inverted quadrangular pyramid (tapered) concaves,thereby removing the silicon nitride layer. Further, the siliconsubstrate was etched, and the dry etching was stopped when the siliconoxide layer provided on the inner wall of the through fine holes wasexposed by a length of 100 μm (sixth step).

[0554] Thus, fine nozzles formed of silicon oxide in communication withthe fine holes of the silicon substrate were formed by the above stepson the etching side of the silicon substrate. The fine nozzles had anopening diameter of the front end portion of 19 μm in a variation within±1 μm and were formed at a pitch of 120 μm with very high accuracy.

Production of Apparatus for Fine Pattern Formation

[0555] Next, a support member of a polyether ether ketone resin, inwhich a flange portion and an opening had been formed, was fixed withthe aid of an epoxy adhesive onto the silicon nitride layer on theperipheral portion of the surface of the silicon substrate (surface inwhich inverted quadrangular pyramid tapered concaves were formed).

[0556] Next, an ink passage formed of a resin pipe was connected to theopening of the support member, and the other end of the resin pipe wasconnected to an ink supplying device (1500 XL, manufactured by EFD).Thus, an apparatus for fine pattern formation according to the presentinvention was prepared.

Formation of Fine Pattern

[0557] The ink supplying device was loaded with ink (Color MosaicCR-7001, manufactured by Fuji Film Olin Co., Ltd.). This ink had aviscosity of 20 mPa.s. Further, a glass substrate (100 mm×100 mm) wasprovided as a pattern object.

[0558] Next, while scanning the glass substrate at a constant speed of50 mm/sec in a direction in which the fine nozzles of the apparatus forfine pattern formation were arranged, ink was supplied from the inksupplying device to the silicon substrate, and ink was ejected throughthe fine nozzles to write a stripe pattern which was then dried. Thestripes constituting the pattern had a line width of 25±1 μm and a linepitch of 25±1 μm, that is, were formed with very high accuracy.

[0559] Further, the ink supplying device was loaded with high-viscosityink. This ink had a viscosity of 100 mPa.s. A strip pattern was writtenand dried in the same manner as described above. The stripesconstituting the pattern had a line width of 30±2 μm and a line pitch of120±1 μm, that is, were formed with very high accuracy.

Example I-4 Production of Fine Nozzles

[0560] A silicon substrate having an RCA cleaned surface (diameter 3in., thickness 200 μm, one side polished, crystallographic orientation<100>, coefficient of linear expansion=2.6×10⁻⁶/K) was provided. Asilicon nitride layer was formed on the whole area of this siliconsubstrate by low pressure CVD to a thickness of 0.1 μm.

[0561] Next, a photosensitive resist (Micro Posit S 1818, manufacturedby Shipley) was coated on the silicon nitride layer, followed byexposure through a predetermined photomask and development to form aresist pattern. Thereafter, dry etching by RIE (reactive ion etching)was carried out using this resist pattern as a mask to form a pattern inwhich 42 small openings (circular openings having a diameter of 30 μm)were formed on an identical straight line at a pitch of 120 μm (firststep).

[0562] Next, a 0.2 μm-thick thin film of aluminum was sputtered on bothsurfaces of the silicon substrate so as to cover the silicon nitridelayer pattern. A photosensitive resist (Micro Posit S 1818, manufacturedby Shipley) was then coated on the thin film of aluminum located on thesmall opening formed surface, followed by exposure through apredetermined photomask and development to form a resist pattern.Thereafter, the thin film of aluminum was etched with an aluminumetchant (mixed acid aluminum) using this resist pattern as a mask, andthe resist pattern was then removed to form a metal pattern in whichfine openings (circular openings having a diameter of 20 μm) werelocated in the center of the respective small openings. Further, aphotosensitive resist (Micro Posit S 1818, manufactured by Shipley) wascoated on the thin film of aluminum located on the surface remote fromthe small openings, followed by exposure through a predeterminedphotomask and development to form a resist pattern. Thereafter, the thinfilm of aluminum was etched with an aluminum etchant (mixed acidaluminum) using this resist pattern as a mask, and the resist patternwas then removed to form wide openings (circular openings having adiameter of 50 μm). In this case, the wide openings were formed in sucha manner that the center of the wide opening conformed to the center ofthe small opening through the silicon substrate (second step).

[0563] Next, the silicon substrate was deeply etched by ICP-RIE(inductively coupled plasma-reactive ion etching) using the metalpattern having fine openings as a mask to form fine holes having a depthof 150 μm (diameter 20 μm) in the silicon substrate (third step).

[0564] The silicon substrate was then deeply etched by ICP-RIE(inductively coupled plasma-reactive ion etching) using the metalpattern having wide openings as a mask until the fine holes appeared,that is, to a depth of about 50 μm. As a result, circular wide concaveshaving a diameter of 50 μm were formed. In these wide concaves, theopenings of the fine holes were located in the center of the bottom ofthe wide concaves (fourth step).

[0565] Next, the metal pattern was separated and removed with sulfuricacid-aqueous hydrogen peroxide (sulfuric acid: aqueous hydrogenperoxide=1:1), and the silicon substrate was oxidized within a thermaloxidation furnace under the following conditions to form an about 5000to 10000 angstrom-thick silicon oxide layer on the wall surface of thewide concaves, on the wall surface of the fine holes, and on the siliconsubstrate in its portions exposed within the small openings of thesilicon nitride layer pattern (fifth step).

[0566] (Conditions for thermal oxidation)

[0567] Heating temperature: 1100° C.

[0568] Oxygen gas feed rate: 1 L/min

[0569] Heating time: about 5 hr

[0570] Next, dry etching by ICP-RIE (inductively coupled plasma-reactiveion etching) was carried out from the surface side of the siliconsubstrate remote from the wide concaves. In this dry etching, thesilicon oxide layer functioned as a mask to form nozzle bases integrallywith the silicon substrate, and the dry etching was stopped when thelength of the nozzle bases reached 100 μm (sixth step).

[0571] Thus, fine nozzles comprising nozzle bases, an inner surfacelayer of silicon oxide in communication with the fine holes in thesilicon substrate, and an end face layer of silicon oxide formed on thefront end face of the nozzle bases were prepared by the above steps onthe etching side of the silicon substrate. The fine nozzles had anopening diameter of the front end portion of 20 μm in a variation within±1 μm and were formed at a pitch of 120 μm with very high accuracy. Thewall thickness (5 μm) of the nozzle bases was provided as a differencein radius between the small openings and the fine openings.

Production of Apparatus for Fine Pattern Formation

[0572] Next, a support member of a polyether ether ketone resin, inwhich a flange portion and an opening had been formed, was fixed withthe aid of an epoxy adhesive on the peripheral portion of the surface ofthe silicon substrate (surface remote from the fine nozzles).

[0573] Next, an ink passage formed of a resin pipe was connected to theopening of the support member, and the other end of the resin pipe wasconnected to an ink supplying device (1500 XL, manufactured by EFD).Thus, an apparatus for fine pattern formation according to the presentinvention was prepared.

Formation of Fine Pattern

[0574] The ink supplying device was loaded with ink (Color MosaicCR-7001, manufactured by Fuji Film Olin Co., Ltd.). This ink had aviscosity of 50 mPa.s. Further, a glass substrate (100 mm×100 mm) wasprovided as a pattern object.

[0575] Next, while scanning the glass substrate at a constant speed of50 mm/sec in a direction in which the fine nozzles of the apparatus forfine pattern formation were arranged, ink was supplied from the inksupplying device to the silicon substrate, and ink was ejected throughthe fine nozzles to write a stripe pattern which was then dried. Thestripes constituting the pattern had a line width of 25±1 μm and a linepitch of 25±1 μm, that is, were formed with very high accuracy.

[0576] Further, the ink supplying device was loaded with high-viscosityink. This ink had a viscosity of 100 mPa.s. A strip pattern was writtenand dried in the same manner as described above. The stripesconstituting the pattern had a line width of 40±1 μm and a line pitch of120±1 μm, that is, were formed with very high accuracy.

Example II-1 Formation of Fine Nozzles

[0577] A silicon substrate having an RCA cleaned surface (diameter 3in., thickness 200 μm, one side polished, crystallographic orientation<100>, coefficient of linear expansion=2.6×10⁻⁶/K) was first provided. Asilicon nitride layer was formed on the whole area of this siliconsubstrate by low pressure CVD to a thickness of 0.1 μm. Thereafter, a0.2 μm-thick thin film of aluminum was sputtered on the silicon nitridelayer located on one surface of the silicon substrate.

[0578] Next, a photosensitive resist (Micro Posit S 1818, manufacturedby Shipley) was coated on the thin film of aluminum, followed byexposure through a predetermined photomask and development to form aresist pattern. Thereafter, the thin film of aluminum was etched with analuminum etchant (mixed acid aluminum) using the resist pattern as amask, and the resist pattern was then removed to form a metal pattern inwhich 23 fine openings (circular openings having a diameter of 20 μm)are formed on an identical straight line at a pitch of 200 μm.

[0579] Next, the silicon substrate was deeply etched by ICP-RIE(inductively coupled plasma-reactive ion etching) using the metalpattern as a mask to form through fine holes (diameter 20 μm) in thesilicon substrate.

[0580] Next, the metal pattern was separated and removed with sulfuricacid-aqueous hydrogen peroxide (sulfuric acid: aqueous hydrogenperoxide=1:1), and the silicon substrate was oxidized within a thermaloxidation furnace under the following conditions to form an about 5000to 10000 angstrom-thick silicon oxide layer on the wall surface of thethrough fine holes.

[0581] (Conditions for thermal oxidation)

[0582] Heating temperature: 1100° C.

[0583] Oxygen gas feed rate: 1 L/min

[0584] Heating time: about 5 hr

[0585] Next, dry etching by ICP-RIE (inductively coupled plasma-reactiveion etching) was carried out from the silicon substrate on its surfacewhere the metal pattern had been provided, thereby removing the siliconnitride layer. Further, the silicon substrate was etched, and the dryetching was stopped when the silicon oxide layer provided on the innerwall of the through fine holes was exposed by a length of 136 μm.

[0586] Thus, fine nozzles formed of silicon oxide in communication withthe fine holes of the silicon substrate were formed by the above stepson the etching side of the silicon substrate. The fine nozzles had anopening diameter of the front end portion of 23 μm, an outer diameter of24 μm, a wall thickness around the front end portion of 0.5 μm and wereformed at a pitch of 200 μm.

Formation of Reinforcing Layer

[0587] A reinforcing layer was formed by plasma CVD under the followingconditions from the fine nozzle-formed surface side of the siliconsubstrate with the fine nozzles formed thereon.

[0588] (Conditions for formation of reinforcing layer)

[0589] Plasma CVD device: PED-401, manufactured by Anelva

[0590] Power: 150 kW

[0591] Frequency: 90 kHz

[0592] Pressure in process: 2.9×10⁻¹ Torr (38.6 Pa)

[0593] Gas flow rate:

[0594] Oxygen flow rate=30 sccm

[0595] Helium flow rate=30 sccm

[0596] Hexamethyldisiloxane flow rate=0.1 sccm (liquid)

[0597] Film formation time: 6 min

[0598] The fine nozzles after the formation of the reinforcing layer ofsilicon oxide by the above method had an opening diameter of the frontend portion of 20 μm, an outer diameter of 26 μm, and a wall thicknessaround the front end portion of 3.0 μm.

Measurement of Strength of Fine Nozzles

[0599] A comparison of the strength between the fine nozzles before theformation of the reinforcing layer and the fine nozzles after theformation of the reinforcing layer was done by the following method.Specifically, the silicon substrate was placed horizontally so that theaxial direction of the fine nozzles was vertical. A universal bondtester PC-2400 manufactured by Dage was provided, and a shear testingload cell was disposed while keeping a distance of about 5 μm betweenthe front end of the cell and the surface of the silicon substrate andwas collided against three fine nozzles at the same time in thehorizontal direction at a speed of 6 mm/min to break the fine nozzles.The strength at that time was measured. As a result, the strength of thefine nozzles before the formation of the reinforcing layer was 0.16 gper nozzle, and the strength of the fine nozzles after the formation ofthe reinforcing layer was 0.68 g per nozzle. From this result, it wasconfirmed that the formation of a reinforcing layer significantlyimproved the strength of the fine nozzles (4.3 times).

Formation of Water-Repellent Layer

[0600] A water-repellent layer was formed by plasma CVD under thefollowing conditions from the fine nozzle formed surface side of thesilicon substrate with the reinforcing layer formed thereon.

[0601] (Conditions for formation of water-repellent layer)

[0602] Plasma CVD device: PED-401, manufactured by Anelva

[0603] Power: 50 W

[0604] Frequency: 13.56 MHz

[0605] Base pressure: 4.0×10⁻⁵ Torr (5.3×10⁻³ Pa)

[0606] Pressure in process: 1.1×10⁻¹ Torr (14.6 Pa)

[0607] Process gas: CHF₃

[0608] Gas flow rate: 100 sccm

[0609] Film formation time: 10 min

[0610] The water-repellent layer thus formed was analyzed by thefollowing ESCA (electron spectroscopy for chemical analysis) and FT-IR(fourier transform infrared spectroscopy). As a result, it was confirmedthat, in the water-repellent layer, most of carbon elements were in theform of a fluorinated alkyl chain and the ratio of the number of carbonelements to the number of fluorine elements was 1:1.05. The thickness ofthe water-repellent layer was 37 nm. Further, the contact angle of thewater-repellent layer with water was measured and was found to be about95 degrees. This contact angle was much larger than the contact angle ofthe reinforcing layer with water measured in the same manner as used inthe water-repellent layer, i.e., 60 degrees, indicating that thewater-repellent layer had excellent water repellency.

[0611] (ESCA)

[0612] Apparatus: ESCALAB 220i-XL, manufactured by VG Scientific

[0613] X-ray source: Monochromated Al Kα

[0614] Output of X-ray: 10 kV·15 mA (150 W)

[0615] Lens: Large Area XL

[0616] Substrate: Silicon wafer (FT-IR)

[0617] Apparatus: FT/IR-610, manufactured by Japan Spectroscopic Co.,Ltd.

[0618] Measurement mode: Macro-TRS transmission measurement

[0619] Resolution: 4 cm⁻¹

[0620] Integrated number: 128 times

[0621] Substrate: Silicon wafer

Production of Apparatus for Fine Pattern Formation

[0622] Next, a support member of a polyether ether ketone resin, inwhich a flange portion and an opening had been formed, was fixed withthe aid of an epoxy adhesive onto the silicon nitride layer on theperipheral portion of the surface of the silicon substrate (surfaceremote from the fine nozzles).

[0623] Next, an ink passage formed of a resin pipe was connected to theopening of the support member, and the other end of the resin pipe wasconnected to an ink supplying device (1500 XL, manufactured by EFD).Thus, an apparatus for fine pattern formation according to the presentinvention was prepared.

Formation of Fine Pattern

[0624] The ink supplying device was loaded with ink (Color MosaicCR-7001, manufactured by Fuji Film Olin Co., Ltd.). Further, a glasssubstrate (100 mm×100 mm) was provided as a pattern object.

[0625] Next, while scanning the glass substrate at a constant speed of50 mm/sec in a direction in which the fine nozzles of the apparatus forfine pattern formation were arranged, ink was supplied from the inksupplying device to the silicon substrate, and ink was ejected throughthe fine nozzles to write a stripe pattern which was then dried. Thestripes constituting the pattern had a line width of 25±1 μm and a linepitch of 25±1 μm, that is, were formed with very high accuracy.

[0626] Further, substantially no deposition of ink onto the back surfaceof the silicon substrate in the apparatus for fine pattern formation wasfound.

Example II-2 Production of Fine Nozzles

[0627] A silicon substrate having an RCA cleaned surface (diameter 3in., thickness 200 μm, one side polished, crystallographic orientation<100>, coefficient of linear expansion=2.6×10⁻⁶/K) was provided. Asilicon nitride layer was formed on the whole area of this siliconsubstrate by low pressure CVD to a thickness of 0.1 μm.

[0628] Next, a photosensitive resist (Micro Posit S 1818, manufacturedby Shipley) was coated on the silicon nitride layer, followed byexposure through a predetermined photomask and development to form aresist pattern. Thereafter, dry etching by RIE (reactive ion etching)was carried out using this resist pattern as a mask to form a pattern inwhich 23 openings for taper (square openings having a one side length of70 μm) were formed on an identical straight line at a pitch of 220 μm.Further, a photosensitive resist was coated on the silicon nitride layerin its portion located on the back surface of the silicon substrate, foruse as a mask for subsequent crystallographically anisotropic etching.

[0629] Next, the surface of the silicon substrate was subjected tocrystallographically anisotropic etching using the silicon nitride layeras a mask. This etching was carried out by immersing the substrate in a33 vol % aqueous potassium hydroxide solution kept at 70 to 80° C. forabout 50 min. As a result, inverted quadrangular pyramid concaves, whichhad a depth of 50 μm and had an angle of one side to the surface of thesilicon substrate of 55 degrees, were formed in the silicon substrate inits portions exposed to openings for taper.

[0630] Next, the resist pattern was removed, and a 0.2 μm-thick thinfilm of aluminum was sputtered on both surfaces of the siliconsubstrate. A photosensitive resist (Micro Posit S 1818, manufactured byShipley) was then coated on the thin film of aluminum in its portionlocated on the surface remote from the inverted quadrangular pyramidconcaves, followed by exposure through a predetermined photomask anddevelopment to form a resist pattern. Thereafter, the thin film ofaluminum was etched with an aluminum etchant (mixed acid aluminum) usingthis resist pattern as a mask, and the resist pattern was then removedto form a metal pattern in which 23 fine openings (circular openingshaving a diameter of 20 μm) were formed on an identical straight line ata pitch of 220 μm. In this case, the metal pattern was formed in such amanner that the center of the fine opening conformed to the center ofthe opening in the inverted quadrangular pyramid concave (the apex ofthe taper) through the silicon substrate.

[0631] Next, the silicon substrate was deeply etched by ICP-RIE(inductively coupled plasma-reactive ion etching) using the metalpattern as a mask to form fine holes (diameter 20 μm) in the siliconsubstrate. In this deep etching, the thin film of aluminum formed withinthe inverted quadrangular pyramid concaves functioned as a stoppinglayer.

[0632] Next, the metal pattern was separated and removed with sulfuricacid-aqueous hydrogen peroxide (sulfuric acid: aqueous hydrogenperoxide=1:1), and the silicon substrate was oxidized within a thermaloxidation furnace under the following conditions to form an about 5000to 10000 angstrom-thick silicon oxide layer on the wall surface of theinverted quadrangular pyramid concaves and on the wall surface of thethrough fine holes.

[0633] (Conditions for thermal oxidation)

[0634] Heating temperature: 1100° C.

[0635] Oxygen gas feed rate: 1 L/min

[0636] Heating time: about 5 hr

[0637] Next, the silicon nitride layer was removed, and dry etching byICP-RIE (inductively coupled plasma-reactive ion etching) was thencarried out from the silicon substrate on its surface side remote fromthe inverted quadrangular pyramid (tapered) concaves. Further, thesilicon substrate was etched, and the dry etching was stopped when thesilicon oxide layer provided on the inner wall of the through fine holeswas exposed by a length of 100 μm.

[0638] Thus, fine nozzles formed of silicon oxide in communication withthe fine holes of the silicon substrate were formed by the above stepson the etching side of the silicon substrate. The fine nozzles had anopening diameter of the front end portion of 23 μm, an outer diameter of24 μm, and a wall thickness around the front end portion of 0.5 μm andwere formed at a pitch of 220 μm.

Formation of Reinforcing Layer

[0639] A reinforcing layer was formed by plasma CVD under the followingconditions from the fine nozzle formed surface side of the siliconsubstrate with the fine nozzles formed thereon.

[0640] (Conditions for formation of reinforcing layer)

[0641] Plasma CVD device: PED-401, manufactured by Anelva

[0642] Power: 150 kW

[0643] Frequency: 90 kHz

[0644] Pressure in process: 2.9×10⁻¹ Torr (38.6 Pa)

[0645] Gas flow rate:

[0646] Oxygen flow rate=30 sccm

[0647] Helium flow rate=30 sccm

[0648] Hexamethyldisiloxane flow rate=0.1 sccm (liquid)

[0649] Film formation time: 6 min

[0650] The fine nozzles after the formation of the reinforcing layer ofsilicon oxide had an opening diameter of the front end portion of 20 μm,an outer diameter of 26 μm, and a wall thickness around the front endportion of 3.0 μm.

Formation of Water-Repellent Layer

[0651] In the same manner as in Example 1, a water-repellent layer wasformed by plasma CVD from the fine nozzle formed surface side of thesilicon substrate with the reinforcing layer formed thereon.

[0652] The water-repellent layer thus formed was analyzed by ESCA andFT-IR in the same manner as in Example 1. As a result, it was confirmedthat, in the water-repellent layer, most of carbon elements were in theform of a fluorinated alkyl chain and the ratio of the number of carbonelements to the number of fluorine elements was 1:1.05. The thickness ofthe water-repellent layer was 37 nm. Further, the contact angle of thewater-repellent layer with water was measured and was found to be about95 degrees. This contact angle was much larger than the contact angle ofthe reinforcing layer with water measured in the same manner as used inthe water-repellent layer, i.e., 60 degrees, indicating that thewater-repellent layer had excellent water repellency.

Production of Apparatus for Fine Pattern Formation

[0653] Next, a support member of a polyether ether ketone resin, inwhich a flange portion and an opening had been formed, was fixed withthe aid of an epoxy adhesive on the peripheral portion of the surface ofthe silicon substrate (surface in which inverted quadrangular pyramidtapered concaves were formed).

[0654] Next, an ink passage formed of a resin pipe was connected to theopening of the support member, and the other end of the resin pipe wasconnected to an ink supplying device (1500 XL, manufactured by EFD).Thus, an apparatus for fine pattern formation according to the presentinvention was prepared.

Formation of Fine Pattern

[0655] The ink supplying device was loaded with ink (Color MosaicCR-7001, manufactured by Fuji Film Olin Co., Ltd. ). This ink had aviscosity of 20 mPa.s. Further, a glass substrate (100 mm×100 mm) wasprovided as a pattern object.

[0656] Next, while scanning the glass substrate at a constant speed of50 mm/sec in a direction in which the fine nozzles of the apparatus forfine pattern formation were arranged, ink was supplied from the inksupplying device to the silicon substrate, and ink was ejected throughthe fine nozzles to write a stripe pattern which was then dried. Thestripes constituting the pattern had a line width of 25±1 μm and a linepitch of 25±1 μm, that is, were formed with very high accuracy.

[0657] Further, the ink supplying device was loaded with high-viscosityink. This ink had a viscosity of 100 mPa.s. A stripe pattern was writtenand dried in the same manner as described above. The stripesconstituting the pattern had a line width of 30±2 μm and a line pitch of220±1 μm, that is, were formed with very high accuracy.

Example II-3 Production of Fine Nozzles

[0658] A silicon substrate having an RCA cleaned surface (diameter 3in., thickness 200 μm, one side polished, crystallographic orientation<100>, coefficient of linear expansion=2.6×10⁻⁶/K) was provided. Asilicon nitride layer was formed on the whole area of this siliconsubstrate by low pressure CVD to a thickness of 0.1 μm. A thin film ofaluminum was then sputtered on the silicon nitride layer on bothsurfaces of the silicon substrate to a thickness of 0.2 μm.

[0659] Next, a photosensitive resist (Micro Posit S 1818, manufacturedby Shipley) was coated on the thin film of aluminum in its portionlocated on one surface of the silicon substrate, followed by exposurethrough a predetermined photomask and development to form a resistpattern. Thereafter, the thin film of aluminum was etched with analuminum etchant (mixed acid aluminum) using this resist pattern as amask, and the resist pattern was then removed to form a metal patternhaving wide openings (circular openings having a diameter of 50 μm).Further, a photosensitive resist (Micro Posit S 1818, manufactured byShipley) was coated on the thin film of aluminum located on the surfaceremote from the wide openings, followed by exposure through apredetermined photomask and development to form a resist pattern.Thereafter, the thin film of aluminum was etched with an aluminumetchant (mixed acid aluminum) using this resist pattern as a mask, andthe resist pattern was then removed to form a metal pattern having fineopenings (circular openings having a diameter of 20 μm). In this case,the metal pattern was formed in such a manner that the center of thefine opening conformed to the center of the wide opening through thesilicon substrate.

[0660] Next, the silicon substrate was deeply etched by ICP-RIE(inductively coupled plasma-reactive ion etching) using the metalpattern having fine openings as a mask to form fine holes having a depthof 150 μm (diameter 20 μm) in the silicon substrate.

[0661] The silicon substrate was then deeply etched by ICP-RIE(inductively coupled plasma-reactive ion etching) using the metalpattern having wide openings as a mask until the fine holes appeared,that is, to a depth of about 50 μm. As a result, circular wide concaveshaving a diameter of 50 μm were formed. In these wide concaves, theopening of the fine hole was located in the center of the bottom of thewide concave.

[0662] Next, the metal pattern was separated and removed with sulfuricacid-aqueous hydrogen peroxide (sulfuric acid: aqueous hydrogenperoxide=1:1), and the silicon substrate was oxidized within a thermaloxidation furnace under the following conditions to form an about 5000to 10000 angstrom-thick silicon oxide layer on the wall surface of thewide concaves and on the silicon substrate in its portions exposed tothe wall surface of the fine holes.

[0663] (Conditions for thermal oxidation)

[0664] Heating temperature: 1100° C.

[0665] Oxygen gas feed rate: 1 L/min

[0666] Heating time: about 5 hr

[0667] Next, the silicon nitride layer was removed, and dry etching byICP-RIE (inductively coupled plasma-reactive ion etching) was thencarried out from the silicon substrate on its surface side remote fromthe wide concaves. Further, the silicon substrate was etched, and thedry etching was stopped when the silicon oxide layer provided on theinner wall of the through fine holes was exposed by a length of 100 μm.

[0668] Thus, fine nozzles formed of silicon oxide in communication withthe fine holes of the silicon substrate were formed by the above stepson the etching side of the silicon substrate. The fine nozzles had anopening diameter of the front end portion of 23 μm, an outer diameter of24 μm, and a wall thickness around the front end portion of 0.5 μm andwere formed at a pitch of 120 μm.

Formation of Reinforcing Layer

[0669] A reinforcing layer was formed by plasma CVD under the followingconditions from the fine nozzle formed surface side of the siliconsubstrate with the fine nozzles formed thereon.

[0670] (Conditions for formation of reinforcing layer)

[0671] Plasma CVD device: PED-401, manufactured by Anelva

[0672] Power: 150 kW

[0673] Frequency: 90 kHz

[0674] Pressure in process: 2.9×10⁻¹ Torr (38.6 Pa)

[0675] Gas flow rate:

[0676] Oxygen flow rate=30 sccm

[0677] Helium flow rate=30 sccm

[0678] Hexamethyldisiloxane flow rate=0.1 sccm (liquid)

[0679] Film formation time: 6 min

[0680] The fine nozzles after the formation of the reinforcing layer ofsilicon oxide had an opening diameter of the front end portion of 20 μm,an outer diameter of 26 μm, and a wall thickness around the front endportion of 3.0 μm.

Formation of Water-Repellent Layer

[0681] In the same manner as in Example 1, a water-repellent layer wasformed by plasma CVD from the fine nozzle formed surface side of thesilicon substrate with the reinforcing layer formed thereon.

[0682] The water-repellent layer thus formed was analyzed by ESCA andFT-IR in the same manner as in Example 1. As a result, it was confirmedthat, in the water-repellent layer, most of carbon elements were in theform of a fluorinated alkyl chain and the ratio of the number of carbonelements to the number of fluorine elements was 1:1.05. The thickness ofthe water-repellent layer was 37 nm. Further, the contact angle of thewater-repellent layer with water was measured and was found to be about95 degrees. This contact angle was much larger than the contact angle ofthe reinforcing layer with water measured in the same manner as used inthe water-repellent layer, i.e., 60 degrees, indicating that thewater-repellent layer had excellent water repellency.

Production of Apparatus for Fine Pattern Formation

[0683] Next, a support member of a polyether ether ketone resin, inwhich a flange portion and an opening had been formed, was fixed withthe aid of an epoxy adhesive on the peripheral portion of the surface ofthe silicon substrate (surface in which multistaged concave openingswere formed).

[0684] Next, an ink passage formed of a resin pipe was connected to theopening of the support member, and the other end of the resin pipe wasconnected to an ink supplying device (1500 XL, manufactured by EFD).Thus, an apparatus for fine pattern formation according to the presentinvention was prepared.

Formation of Fine Pattern

[0685] The ink supplying device was loaded with ink (Color MosaicCR-7001, manufactured by Fuji Film Olin Co., Ltd.). This ink had aviscosity of 20 mPa.s. Further, a glass substrate (100 mm×100 mm) wasprovided as a pattern object.

[0686] Next, while scanning the glass substrate at a constant speed of50 mm/sec in a direction in which the fine nozzles of the apparatus forfine pattern formation were arranged, ink was supplied from the inksupplying device to the silicon substrate, and ink was ejected throughthe fine nozzles to write a stripe pattern which was then dried. Thestripes constituting the pattern had a line width of 25±1 μm and a linepitch of 25±1 μm, that is, were formed with very high accuracy.

[0687] Further, the ink supplying device was loaded with high-viscosityink. This ink had a viscosity of 100 mPa.s. A stripe pattern was writtenand dried in the same manner as described above. The stripesconstituting the pattern had a line width of 28±2 μm and a line pitch of120±1 μm, that is, were formed with very high accuracy.

Example III-1 Preparation of Apparatus for Fine Pattern Formation

[0688] A silicon substrate having a cleaned surface (diameter 3 in.,thickness 200 μm, one side polished, crystallographic orientation <100>,coefficient of linear expansion=2.6×10⁻⁶/K) was provided. This siliconsubstrate was oxidized within a thermal oxidation furnace under thefollowing conditions to form an about 2 μm-thick silicon oxide film onthe whole surface of the silicon substrate.

[0689] (Conditions for thermal oxidation)

[0690] Heating temperature: 1050° C.

[0691] Hydrogen gas feed rate: 1 slm

[0692] Oxygen gas feed rate: 1 slm

[0693] Heating time: about 15 hr

[0694] Next, a photosensitive resist (Micro Posit 1400-31, manufacturedby Shipley) was spin coated on the polished surface side of the siliconsubstrate, and the coating was then dried. Thereafter, exposure througha predetermined photomask and development were carried out to form aresist pattern. This resist pattern had 23 circular openings (diameter20 μm) formed in X-axis direction on an identical line at a pitch of 200μm. BHF 16 (a 22% aqueous solution of ammonium monohydrodifluoride) wasthen used to pattern the silicon oxide film using the resist pattern asa mask and to dissolve and remove the silicon oxide film at sites whereno resist pattern was provided.

[0695] High aspect etching by ICP-RIE (inductively coupledplasma-reactive ion etching) was then carried out using the patternedresist pattern and the silicon oxide film as a mask to form fine holeshaving a diameter of 20 μm and a depth of 190 μm. Thereafter, the resistpattern was removed with a mixed solution composed of sulfuric acid andhydrogen peroxide, and, further, the mask of silicon oxide film wasremoved with hydrofluoric acid.

[0696] Next, the silicon substrate with fine holes formed therein wasoxidized within a thermal oxidation furnace in the same manner asdescribed above, except that the heating time was about 3 hr, whereby anabout 5000 to 10000 angstrom-thick silicon oxide layer was formed on thewhole area of the silicon substrate. The silicon oxide layer was alsoformed on the wall surface of the fine holes by this oxidationtreatment.

[0697] Next, only the back surface side of the silicon substrate wasimmersed in BHF 16 to remove the silicon oxide layer, thereby exposingthe back surface of the silicon substrate. Thereafter, the back surfaceside of the silicon substrate was immersed in TMAH (tetramethylammoniumhydroxide) to perform etching. As a result, fine tubes formed of thesilicon oxide layer produced on the wall surface of the fine holes bythe oxidation treatment was protruded in the back surface of the siliconsubstrate.

[0698] The front end of the fine tubes formed of the silicon oxide layerwas then immersed in BHF 16 to dissolve and remove the silicon oxidelayer, thereby forming openings. Thereafter, the back surface side ofthe silicon substrate was etched with TMAH to form nozzles having alength of 100 μm.

[0699] A reinforcing layer was then formed by plasma CVD under thefollowing conditions from the nozzle formed surface side of the siliconsubstrate with the nozzles formed thereon.

[0700] (Conditions for formation of reinforcing layer)

[0701] Plasma CVD device: PED-401, manufactured by Anelva

[0702] Power: 150 kW

[0703] Frequency: 90 kHz

[0704] Pressure in process: 2.9×10⁻¹ Torr (38.6 Pa)

[0705] Gas flow rate:

[0706] oxygen flow rate=30 sccm

[0707] Helium flow rate=30 sccm

[0708] Hexamethyldisiloxane flow rate=0.1 sccm (liquid)

[0709] Film formation time: 6 min

[0710] The nozzles after the formation of the reinforcing layer ofsilicon oxide had an opening diameter of the front end portion of 20 μm,an outer diameter of 30 μm, and a wall thickness around the front endportion of 5.0 μm.

[0711] A comparison of the strength between the nozzles before theformation of the reinforcing layer and the nozzles after the formationof the reinforcing layer was done by the following method. Specifically,the silicon substrate was placed horizontally so that the axialdirection of the nozzles was vertical. A universal bond tester PC-2400manufactured by Dage was provided, and a shear testing load cell wasdisposed while keeping a distance of about 5 μm between the front end ofthe cell and the surface of the silicon substrate and was collidedagainst three nozzles at the same time in the horizontal direction at aspeed of 6 mm/min to break the nozzles. The strength at that time wasmeasured. As a result, the strength of the nozzles before the formationof the reinforcing layer was 0.15 g per nozzle, and the strength of thenozzles after the formation of the reinforcing layer was 0.6 g pernozzle. From this result, it was confirmed that the formation of areinforcing layer significantly improved the strength of the nozzles (4times).

[0712] Next, a main electrode fabricated from an aluminum foil wasprovided on the surface of the silicon substrate so as to surround the23 fine holes formed on an identical line at a pitch of 200 μm. In thiscase, a polyimide layer (thickness 70 μm) for insulation was providedbetween the main electrode and the silicon substrate.

[0713] Next, a support member of a polyether ether ketone resin, inwhich a flange portion and an opening had been formed, was fixed withthe aid of an epoxy adhesive on the peripheral portion of the surfaceside of the silicon substrate (fine hole formed side).

[0714] Next, an ink passage formed of a resin pipe was connected to theopening of the support member, and the other end of the resin pipe wasconnected to an ink supplying device (1500 XL, manufactured by EFD).

[0715] On the other hand, a drum (diameter 10 cm) serving both as apattern object and a counter electrode was rotatably provided so thatthe drum faced the back surface of the silicon substrate and thedirection of the shaft conformed to the arrangement direction of the 23fine holes formed at a pitch of 200 μm. Further, the drum was grounded.The distance from the surface of the drum to the front end of thenozzles was 150 μm. As a result, an apparatus for fine pattern formation(apparatus 1) according to the present invention was prepared. Thisapparatus for fine pattern formation was used for the observation ofejection which will be described later.

[0716] Further, a glass substrate (a pattern object serving also as acounter electrode) having indium tin oxide (ITO) on its surface wasprovided and was grounded. The distance from the surface of the ITOelectrode in the glass substrate to the front end of the nozzles in thesilicon substrate was 250 μm, and a construction was adopted wherein thesilicon substrate could be scanned parallel to the glass substrate. As aresult, an apparatus for fine pattern formation (apparatus 2) accordingto the present invention was prepared. This apparatus for fine patternformation was used for direct writing experiments which will bedescribed later.

Formation of Fine Pattern

[0717] A resin (KC 7000, manufactured by Kyoeisha Chemical Co., Ltd.) (6levels of 0% by weight, 6% by weight, 8% by weight, 12% by weight, 15%by weight, and 17% by weight) was first mixed with butyl carbitol(electric conductivity=1.3×10⁻⁷ S/cm) as a solvent, and the mixtureswere supersonically stirred to prepare solvents. To the solvents wereadded 1% by weight of a red dye (C.I. Disperse Red 60). Thus, six inkswere prepared. The content of resin in the inks, the viscosity of theinks, and the electric conductivity of the inks were as shown in Table 1below. TABLE 1 Resin Viscosity of Electric Ink content, wt % ink, mPa.sconductivity, S/cm Sample 1 0 7 1.3 × 10⁻⁷ Sample 2 6 70 4.2 × 10⁻⁷Sample 3 8 130 4.5 × 10⁻⁷ Sample 4 12 450 5.4 × 10⁻⁷ Sample 5 15 18005.4 × 10⁻⁷ Sample 6 17 2800 5.3 × 10⁻⁷

[0718] Next, the ink supplying device was loaded with each ink preparedabove, and the observation of the ejection of the ink and a directwriting test were carried out.

Observation of Ejection

[0719] Next, a voltage (direct current 1 kV) was applied from a powersource (comprising a function generator, an amplifier (×1000), and anoscilloscope) to the main electrode in the apparatus for fine patternformation (apparatus 1), and the counter electrode was rotated(peripheral speed 23.6 mm/sec). Each ink was then supplied from the inksupplying device to the silicon substrate at a pressure of 1.5 psi, andthe ejection of ink from the nozzles was observed through a microscope.As a result, in the ink having the lowest viscosity (sample 1), ameniscus was formed at the front end of the nozzles. On the other hand,in the inks, the viscosity of which had been increased by incorporatinga resin (samples 2 to 6), any meniscus was not formed at the front endof the nozzles. This is considered attributable to the fact thathigh-viscosity inks were sensitive to an electric field.

Direct Writing Experiment

[0720] A voltage (direct current 1 kV) was applied from a power source(comprising a function generator, an amplifier (×1000), and anoscilloscope) to the main electrode in the apparatus for fine patternformation (apparatus 2), and the silicon substrate was scanned (speed200 mm/sec) relative to the counter electrode (glass substrate providedwith ITO). Each ink was then supplied from the ink supplying device tothe silicon substrate at a pressure of 1.5 psi and was ejected throughthe nozzles to directly write a stripe pattern. As a result, for inksamples 1 to 4 (low-viscosity inks having a viscosity of not more than500 mPa.s), a fine stripe pattern having a line width of 10±1 μm couldbe formed, and, for high-viscosity inks (samples 5 and 6), a finerstripe pattern having a line width up to 2±0.5 μm could be formed.

[0721] Further, a pattern was formed in the same manner as describedabove, except that the voltage applied to the main electrode was 2 kV.As a result, for low-viscosity inks (ink samples 1 to 4), the width ofink ejected from the nozzles was wider. However, the stripe pattern wasformed on the counter electrode (pattern object) in a line width of 12±1μm, that is, was formed with very high accuracy. This demonstrates thatthe ink ejection width can be regulated by varying the strength of fieldformed between the main electrode and the counter electrode.

[0722] On the other hand, low-viscosity ink samples 1 and 2 weresupplied from the ink supplying device to the silicon substrate at apressure of 1.5 psi in the same manner as described above, except thatno voltage was applied to the main electrode. As a result, the inkcannot be ejected through the nozzles. Therefore, the pressure forsupplying the ink from the ink supplying device was increased to 12 psi.As a result, the ejection width of ink from the nozzles became not lessthan 20 μm, and lines overlapped with one another, making it impossibleto form a stripe pattern.

Example III-2 Production of Apparatus for Fine Pattern Formation

[0723] A silicon substrate having an RCA cleaned surface (diameter 3in., thickness 200 μm, one surface polished, crystallographicorientation <100>, coefficient of linear expansion=2.6×10⁻⁶/K) wasprovided. A silicon nitride layer was formed on the whole area of thissilicon substrate by low pressure CVD to a thickness of 0.1 μm.

[0724] Next, a photosensitive resist (Micro Posit S 1818, manufacturedby Shipley) was coated on the silicon nitride layer, followed byexposure through a predetermined photomask and development to form aresist pattern. Thereafter, dry etching by RIE (reactive ion etching)was carried out using this resist pattern as a mask to form a pattern inwhich 23 openings for taper (square openings having a one side length of70 μm) were formed on an identical straight line at a pitch of 120 μm.Further, a photosensitive resist was coated on the silicon nitride layerlocated on the back surface of the silicon substrate, for use as a maskfor subsequent crystallographically anisotropic etching.

[0725] Next, the surface of the silicon substrate was subjected tocrystallographically anisotropic etching using the silicon nitride layeras a mask. This etching was carried out by immersing the substrate in a33 vol % aqueous potassium hydroxide solution kept at 70 to 80° C. forabout 50 min. As a result, inverted quadrangular pyramid concaves, whichhad a depth of 50 μm and had an angle of one side to the surface of thesilicon substrate of 55 degrees, were formed in the silicon substrate inits portions exposed to openings for taper.

[0726] Next, the resist pattern was removed, and a 0.2 μm-thick thinfilm of aluminum was sputtered on both surfaces of the siliconsubstrate. A photosensitive resist (Micro Posit S 1818, manufactured byShipley) was then coated on the thin film of aluminum in its portionlocated on the surface remote from the inverted quadrangular pyramidconcaves, followed by exposure through a predetermined photomask anddevelopment to form a resist pattern. Thereafter, the thin film ofaluminum was etched with an aluminum etchant (mixed acid aluminum) usingthis resist pattern as a mask, and the resist pattern was then removedto form a metal pattern in which 23 fine openings (circular openingshaving a diameter of 20 μm) were formed on an identical straight line ata pitch of 120 μm. In this case, the metal pattern was formed in such amanner that the center of the fine opening conformed to the center ofthe opening in the inverted quadrangular pyramid concave (the apex ofthe taper) through the silicon substrate.

[0727] Next, the silicon substrate was deeply etched by ICP-RIE(inductively coupled plasma-reactive ion etching) using the metalpattern as a mask to form fine holes (diameter 20 μm) in the siliconsubstrate. In this deep etching, the thin film of aluminum formed withinthe inverted quadrangular pyramid concaves functioned as a stoppinglayer.

[0728] Next, the metal pattern was separated and removed with sulfuricacid-aqueous hydrogen peroxide (sulfuric acid: aqueous hydrogenperoxide=1:1), and the silicon substrate was oxidized within a thermaloxidation furnace under the following conditions to form an about 5000to 10000 angstrom-thick silicon oxide layer on the wall surface of theinverted quadrangular pyramid concaves and on the wall surface of thethrough fine holes.

[0729] (Conditions for thermal oxidation)

[0730] Heating temperature: 1100° C.

[0731] Oxygen gas feed rate: 1 L/min

[0732] Heating time: about 5 hr

[0733] Next, the silicon nitride layer was removed, and dry etching byICP-RIE (inductively coupled plasma-reactive ion etching) was thencarried out from the silicon substrate on its surface side remote fromthe inverted quadrangular pyramid (tapered) concaves. Further, thesilicon substrate was etched, and the dry etching was stopped when thesilicon oxide layer provided on the inner wall of the through fine holeswas exposed by a length of 100 μm.

[0734] Thus, nozzles formed of silicon oxide in communication with thefine holes of the silicon substrate were formed by the above steps onthe etching side of the silicon substrate.

[0735] A reinforcing layer was formed by plasma CVD from the nozzleformed surface side of the silicon substrate with the nozzles formedthereon in the same manner as in Example III-1.

[0736] The nozzles after the formation of the reinforcing layer ofsilicon oxide by the above method had an opening diameter of the frontend portion of 20 μm, an outer diameter of 30 μm, a wall thicknessaround the front end portion of 5.0 μm, and a nozzle pitch of 120 μm.

[0737] Next, a main electrode fabricated from an aluminum foil wasprovided on the surface of the silicon substrate so as to surround the23 fine holes formed on an identical line at a pitch of 200 μm. In thiscase, a polyimide layer (thickness 70 μm) for insulation was providedbetween the main electrode and the silicon substrate.

[0738] Next, a support member of a polyether ether ketone resin, inwhich a flange portion and an opening had been formed, was fixed withthe aid of an epoxy adhesive on the peripheral portion of the surfaceside of the silicon substrate (fine hole formed side).

[0739] Next, an ink passage formed of a resin pipe was connected to theopening of the support member, and the other end of the resin pipe wasconnected to an ink supplying device (1500 XL, manufactured by EFD).

[0740] On the other hand, a glass substrate (a pattern object servingalso as a counter electrode) having indium tin oxide (ITO) on itssurface was provided and was grounded. The distance from the surface ofthe ITO electrode in the glass substrate to the front end of the nozzlesin the silicon substrate was 250 μm, and a construction was adoptedwherein the silicon substrate could be scanned parallel to the glasssubstrate. As a result, an apparatus for fine pattern formationaccording to the present invention was prepared.

Formation of Fine Pattern

[0741] Six inks were prepared in the same manner as in Example III-1.Next, the ink supplying device was loaded with each ink prepared above,and an experiment on direct writing was then carried out.

Direct Writing Experiment

[0742] A voltage (direct current 1 kV) was applied from a power source(comprising a function generator, an amplifier (×1000), and anoscilloscope) to the main electrode in the apparatus for fine patternformation, and the silicon substrate was scanned (speed 200 mm/sec)relative to the counter electrode (glass substrate provided with ITO).Each ink was then supplied from the ink supplying device to the siliconsubstrate at a pressure of 1.5 psi and was ejected through the nozzlesto directly write a stripe pattern. As a result, for each of ink samples1 to 6, a fine stripe pattern having a line width of 3±1 μm could beformed.

[0743] Further, a pattern was formed in the same manner as describedabove, except that the voltage applied to the main electrode was 2 kV.As a result, the width of ink ejected from the nozzles was wider.However, the stripe pattern was formed on the counter electrode (patternobject) in a line width of 5±1 μm, that is, was formed with very highaccuracy. This demonstrates that the ink ejection width can be regulatedby varying the strength of field formed between the main electrode andthe counter electrode.

Example III-3 Production of Apparatus for Fine Pattern Formation

[0744] A silicon substrate having an RCA cleaned surface (diameter 3in., thickness 200 μm, one surface polished, crystallographicorientation <100>, coefficient of linear expansion=2.6×10⁻⁶/K) wasprovided. A silicon nitride layer was formed on the whole area of thissilicon substrate by low pressure CVD to a thickness of 0.1 μm. A thinfilm of aluminum was then sputtered on the silicon nitride layer on bothsurfaces of the silicon substrate to a thickness of 0.2 μm.

[0745] Next, a photosensitive resist (Micro Posit S 1818, manufacturedby Shipley) was coated on the thin film of aluminum in its portionlocated on one surface of the silicon substrate, followed by exposurethrough a predetermined photomask and development to form a resistpattern. Thereafter, the thin film of aluminum was etched with analuminum etchant (mixed acid aluminum) using this resist pattern as amask, and the resist pattern was then removed to form a metal patternhaving wide openings (circular openings having a diameter of 50 μm).Further, a photosensitive resist (Micro Posit S 1818, manufactured byShipley) was coated on the thin film of aluminum located on the surfaceremote from the wide openings, followed by exposure through apredetermined photomask and development to form a resist pattern.Thereafter, the thin film of aluminum was etched with an aluminumetchant (mixed acid aluminum) using this resist pattern as a mask, andthe resist pattern was then removed to form a metal pattern having fineopenings (circular openings having a diameter of 20 μm). In this case,the metal pattern was formed in such a manner that the center of thefine opening conformed to the center of the wide opening through thesilicon substrate.

[0746] Next, the silicon substrate was deeply etched by ICP-RIE(inductively coupled plasma-reactive ion etching) using the metalpattern having fine openings as a mask to form fine holes having a depthof 150 μm (diameter 20 μm) in the silicon substrate.

[0747] The silicon substrate was then deeply etched by ICP-RIE(inductively coupled plasma-reactive ion etching) using the metalpattern having wide openings as a mask until the fine holes appeared,that is, to a depth of about 50 μm. As a result, circular wide concaveshaving a diameter of 50 μm were formed. In these wide concaves, theopening of the fine hole was located in the center of the bottom of thewide concave.

[0748] Next, the metal pattern was separated and removed with sulfuricacid-aqueous hydrogen peroxide (sulfuric acid: aqueous hydrogenperoxide=1:1), and the silicon substrate was oxidized within a thermaloxidation furnace under the following conditions to form an about 5000to 10000 angstrom-thick silicon oxide layer on the wall surface of thewide concaves and on the silicon substrate in its portions exposed tothe wall surface of the fine holes.

[0749] (Conditions for thermal oxidation)

[0750] Heating temperature: 1100° C.

[0751] Oxygen gas feed rate: 1 L/min

[0752] Heating time: about 5 hr

[0753] Next, the silicon nitride layer was removed, and dry etching byICP-RIE (inductively coupled plasma-reactive ion etching) was thencarried out from the silicon substrate on its surface side remote fromthe wide concaves. Further, the silicon substrate was etched, and thedry etching was stopped when the silicon oxide layer provided on theinner wall of the through fine holes was exposed by a length of 100 μm.

[0754] Thus, nozzles formed of silicon oxide in communication with thefine holes of the silicon substrate were formed by the above steps onthe etching side of the silicon substrate.

[0755] A reinforcing layer was formed by plasma CVD from the nozzleformed surface side of the silicon substrate with the nozzles formedthereon in the same manner as in Example III-1.

[0756] The nozzles after the formation of the reinforcing layer ofsilicon oxide by the above method had an opening diameter of the frontend portion of 20 μm, an outer diameter of 30 μm, a wall thicknessaround the front end portion of 5.0 μm, and a nozzle pitch of 120 μm.

[0757] Next, a main electrode fabricated from an aluminum foil wasprovided on the surface of the silicon substrate so as to surround the23 fine holes formed on an identical line at a pitch of 200 μm. In thiscase, a polyimide layer (thickness 70 μm) for insulation was providedbetween the main electrode and the silicon substrate.

[0758] Next, a support member of a polyether ether ketone resin, inwhich a flange portion and an opening had been formed, was fixed withthe aid of an epoxy adhesive on the peripheral portion of the surfaceside of the silicon substrate (fine hole formed side).

[0759] Next, an ink passage formed of a resin pipe was connected to theopening of the support member, and the other end of the resin pipe wasconnected to an ink supplying device (1500 XL, manufactured by EFD).

[0760] On the other hand, a glass substrate (a pattern object servingalso as a counter electrode) having indium tin oxide (ITO) on itssurface was provided and was grounded. The distance from the surface ofthe ITO electrode in the glass substrate to the front end of the nozzlesin the silicon substrate was 250 μm, and a construction was adoptedwherein the silicon substrate could be scanned parallel to the glasssubstrate. As a result, an apparatus for fine pattern formationaccording to the present invention was prepared.

Formation of Fine Pattern

[0761] Six inks were prepared in the same manner as in Example III-1.Next, the ink supplying device was loaded with each ink prepared above,and an experiment on direct writing was then carried out.

Direct Writing Experiment

[0762] A voltage (direct current 1 kV) was applied from a power source(comprising a function generator, an amplifier (×1000), and anoscilloscope) to the main electrode in the apparatus for fine patternformation, and the silicon substrate was scanned (speed 200 mm/sec)relative to the counter electrode (glass substrate provided with ITO).Each ink was then supplied from the ink supplying device to the siliconsubstrate at a pressure of 1.5 psi and was ejected through the nozzlesto directly write a stripe pattern. As a result, for each of ink samples1 to 6, a fine stripe pattern having a line width of 3±1 μm could beformed.

[0763] Further, a pattern was formed in the same manner as describedabove, except that the voltage applied to the main electrode was 2 kV.As a result, the width of ink ejected from the nozzles was wider.However, the stripe pattern was formed on the counter electrode (patternobject) in a line width of 5±1 μm, that is, was formed with very highaccuracy. This demonstrates that the ink ejection width can be regulatedby varying the strength of field formed between the main electrode andthe counter electrode.

[0764] As described above in detail, the apparatus for fine patternformation according to the present invention can eject ink through aplurality of fine nozzles on the back surface side of a siliconsubstrate at substantially even ejection width in a very small amountwith high accuracy and, at the same time, can prevent the deposition ofink onto the back surface of the silicon substrate and permits theamount of ink ejected to be set as desired by varying the amount of inksupplied. Therefore, a pattern can be simply and stably formed with highaccuracy by depositing ink onto a pattern object to directly write apattern. The silicon nitride layer provided on the surface and side ofthe silicon substrate imparts a high level of electrically insulatingproperties to the silicon substrate. Further, when the fine nozzles havenozzle bases, the mechanical strength of the fine nozzles is high andthe durability against external impact and ink supply pressure can besignificantly improved. When the openings of the fine holes remote fromfine nozzles are in the form of a tapered or multistaged concave, thepassage resistance is lowered. This can realize the ejection of an inkhaving higher viscosity through a plurality of fine nozzles in asubstantially even ejection width and in a very small amount with highaccuracy.

[0765] In the production process of fine nozzles according to thepresent invention, through fine holes are formed in a silicon substrate,a silicon oxide layer is selectively formed only on an exposed surfaceincluding the inner wall surface of the through fine holes, and finenozzles are formed by utilizing a difference in dry etching rate betweenthe silicon oxide layer and the silicon substrate. Therefore, finenozzles with high inner diameter accuracy can be easily formed. Further,in particular, the utilization of the mask side at the time of deepetching as the front end of nozzles can provide evener opening diameterof the plurality of fine nozzles.

[0766] As described above in detail, in the apparatus for fine patternformation according to the present invention, the fine nozzles have highmechanical strength by virtue of the provision of the reinforcing layerand are satisfactorily durable against external impact and ink supplypressure, and ink can be ejected in a very small amount with highaccuracy through the plurality of fine nozzles on the back surface sideof the silicon substrate. The amount of ink ejected may be set asdesired by varying the amount of ink supplied. Therefore, a pattern canbe stably formed with high accuracy in a simple manner by depositing inkon a pattern object to directly write a pattern. Further, the provisionof a water-repellent layer on the back surface side of the siliconsubstrate and the reinforcing layer can significantly improve theprevention of the deposition of ink. Furthermore, when the openings ofthe fine holes in their surface side are tapered or multistagedconcaves, the passage resistance of ink is reduced and an ink havinghigher viscosity can be ejected in a very small amount with highaccuracy through the plurality of fine nozzles.

[0767] Further, as described above in detail, in the apparatus for finepattern formation according to the present invention, since an electricfield formed between the main electrode and the counter electrode isused in combination with the ink supply pressure as ink ejection means,the ink supply pressure can be set at a low value and ink can be ejectedin a very small amount with high accuracy through the fine holes of thesilicon substrate. When ink is present in the ink supply space, ink canbe ejected by utilizing only an electric field without the ink supplypressure. Further, the ink ejection width can be regulated by varyingthe strength of field formed between the main electrode and the counterelectrode. Therefore, ink can be ejected in a very small amount withhigh accuracy without reducing the opening diameter of the fine holesand without increasing the ink supply pressure. When the nozzles areprovided at the openings of the fine holes, the deposition of ink ontothe back surface of the silicon substrate can be prevented. Further,when the openings of the fine holes on the surface side are tapered ormultistaged concaves, the passage resistance of ink can be reduced andan ink having higher viscosity can be ejected in a very small amountwith high accuracy through the plurality of fine holes or nozzles. Theamount of ink ejected can be set as desired by varying the amount of inksupplied. Therefore, a pattern can be stably formed with high accuracyin a simple manner by depositing ink on a pattern object to directlywrite a pattern.

[0768] In the method for pattern formation wherein the apparatus forfine pattern formation according to the present invention and a patternobject are scanned relative to each other, a stripe pattern or a dotpattern can be formed with high accuracy. The ejection of ink through aplurality of fine holes arrayed on an identical line along the scanningdirection can enhance the pattern formation speed even when the amountof ink ejected through one fine hole is small. Further, in the methodfor pattern formation wherein the apparatus for fine pattern formationaccording to the present invention is installed at and registered with apredetermined position of the pattern object and a given amount of inkis ejected from each fine hole, a desired pattern can be repeatedlyformed with high accuracy in a simple manner. Therefore, this method isapplicable, for example, to color filters in a matrix form or theformation of a conductor pattern in printed wiring boards. Further, theregulation of the ink ejection width can realize the formation ofpatterns in various forms with higher accuracy.

1. An apparatus for fine pattern formation comprising: a siliconsubstrate; a plurality of fine holes which extend through the siliconsubstrate from a surface of the silicon substrate to a back surface ofthe silicon substrate and have a silicon oxide layer on a wall surfacethereof; fine nozzles which are protruded, integrally with the siliconoxide layer, on the back surface side of the silicon substrate from eachopening of the fine holes; a silicon nitride layer provided on thesurface and side of the silicon substrate; a support member provided onthe surface side of the silicon substrate; an ink passage for supplyingink to the opening of each fine hole on the surface side of the siliconsubstrate; and an ink supplying device connected to the ink passage. 2.The apparatus for fine pattern formation according to claim 1, whereinthe diameter of the openings in the fine nozzles is in the range of 1 to100 μm in a variation within ±1 μm and the fine nozzles are provided ata pitch in the range of 2 to 1000 μm.
 3. An apparatus for fine patternformation, comprising: a silicon substrate; a plurality of fine nozzlesprotruded from the back surface of the silicon substrate; a plurality offine holes which extend at fine nozzle formed sites through the siliconsubstrate from the surface of the silicon substrate to the back surfaceof the silicon substrate and have a silicon oxide layer on the wallsurface thereof; a support member provided on the surface side of thesilicon substrate; an ink passage for supplying ink to the opening ofeach fine hole on the surface side of the silicon substrate; and an inksupplying device connected to the ink passage, said fine nozzles eachcomprising a nozzle base provided integrally with the silicon substrate,an inner surface layer of silicon oxide provided on the inner wallsurface of nozzle bases in communication with the fine holes, and an endface layer of silicon oxide provided integrally with the inner surfacelayer of silicon oxide so as to cover the front end face of the nozzlebases. 4.The apparatus for fine pattern formation according to claim 3,wherein the diameter of the openings in the fine nozzles is in the rangeof 1 to 100 μm in a variation within ±1 μm and the fine nozzles areprovided at a pitch in the range of 4 to 1000 μm.
 5. The apparatus forfine pattern formation according to any one of claims 1 to 4, whereinthe protrusion length of the fine nozzles is in the range of 1 to 150μm.
 6. The apparatus for fine pattern formation according to any one ofclaims 1 to 5, wherein the fine holes in their openings on the surfaceside of the silicon substrate are in the form of tapered concaves whichhave been widened toward the surface side of the silicon substrate. 7.The apparatus for fine pattern formation according to any one of claims1 to 5, wherein the fine holes in their openings on the surface side ofthe silicon substrate are in the form of multistaged concaves which havebeen widened toward the surface side of the silicon substrate.
 8. Theapparatus for fine pattern formation according to any one of claims 1 to7, wherein fine holes are divided into two or more groups and inkpassages are provided separately from each other or one another forrespective fine hole groups.
 9. A process for producing a plurality offine nozzles, formed of silicon oxide, protruded from one surface of asilicon substrate and in communication with fine holes which extendthrough the silicon substrate and have a silicon oxide layer on the wallsurface thereof, said process comprising: a first step of providing asilicon substrate having on its whole surface a silicon nitride layerand forming a mask pattern having a plurality of fine openings on thesilicon nitride layer in its portion located on one surface of thesilicon substrate; a second step of forming through fine holes in thesilicon substrate by deep etching using the mask pattern as a mask; athird step of removing the mask pattern and oxidizing the inside of thethrough fine holes of the silicon substrate to form a silicon oxidelayer; and a fourth step of removing a part of the silicon nitride layerand a part of the silicon substrate from one surface of the siliconsubstrate by dry etching to expose the silicon oxide layer by apredetermined length, thereby forming fine nozzles.
 10. The process forproducing fine nozzles according to claim 9, wherein, in the fourthstep, etching is started with the surface from which the mask patternhas been removed.
 11. A process for producing a plurality of finenozzles protruded from one surface of a silicon substrate, said finenozzles comprising a nozzle base, provided integrally with the siliconsubstrate, and a silicon oxide end face layer covering the front endface of the nozzle base, said nozzle base being in communication withfine holes, which extend through the silicon substrate and have asilicon oxide layer on the wall surface thereof, and having a siliconoxide inner surface layer on its inner wall surface, said processcomprising: a first step of providing a silicon substrate having on itswhole surface a silicon nitride layer and patterning the silicon nitridelayer in its portion located on one surface of the silicon substrate toform a pattern having a plurality of small openings; a second step offorming a mask thin film so as to cover the pattern of the siliconnitride layer and patterning the mask thin film to form a mask patternhaving fine openings located within the small openings; a third step offorming through fine holes in the silicon substrate by deep etchingusing the mask pattern as a mask; a fourth step of removing the maskpattern and oxidizing sites within the through fine holes in thesilicone substrate and sites exposed within the small openings to form asilicon oxide layer; a fifth step of removing the silicon nitride layerand removing a part of the silicon substrate by dry etching using thesilicon oxide layer as a mask from the surface side, on which thesilicon oxide layer has been formed, to form nozzle bases having apredetermined length, thereby forming fine nozzles.
 12. A process forproducing a plurality of fine nozzles, formed of silicon oxide,protruded from one surface of a silicon substrate and in communicationwith fine holes which extend through the silicon substrate and have asilicon oxide layer on the wall surface thereof, said processcomprising: a first step of providing a silicon substrate of <100>surface crystal orientation having on its whole surface a siliconnitride layer and patterning the silicon nitride layer in its portionlocated on one surface side of the silicon substrate to form a patternhaving a plurality of openings for taper; a second step of etching thesurface of the silicon substrate by crystallographically anisotropicetching using the silicon nitride layer as a mask to form taperedconcaves; a third step of forming a mask thin film on both surfaces ofthe silicon substrate and patterning the mask thin film in its portionlocated on the surface of the silicon substrate remote from the taperedconcaves to form a mask pattern having fine openings such that thecenter of each fine opening substantially conforms to the center of eachtapered concave through the silicon substrate; a fourth step of formingthrough fine holes in the silicon substrate by deep etching using, as amask, the mask pattern and the mask thin film; a fifth step of removingthe mask pattern and the mask thin film and oxidizing sites within thethrough fine holes in the silicone substrate and sites exposed withinthe tapered concaves to form a silicon oxide layer; and a sixth step ofremoving a part of the silicon nitride layer and a part of the siliconsubstrate by dry etching from the surface side of the silicon substrateremote from the tapered concaves to expose the silicon oxide layer by apredetermined length, thereby forming fine nozzles.
 13. A process forproducing a plurality of fine nozzles protruded from one surface of asilicon substrate, said fine nozzles comprising a nozzle base, providedintegrally with the silicon substrate, and a silicon oxide end facelayer covering the front end face of the nozzle base, said nozzle basebeing in communication with fine holes, which extend through the siliconsubstrate and have a silicon oxide layer on the wall surface thereof,and having a silicon oxide inner surface layer on its inner wallsurface, said process comprising: a first step of providing a siliconsubstrate of <100> surface crystal orientation having on its wholesurface a silicon nitride layer and patterning the silicon nitride layerin its portion located on one surface side of the silicon substrate toform a pattern having a plurality of openings for taper; a second stepof etching the surface of the silicon substrate by crystallographicallyanisotropic etching using the silicon nitride layer as a mask to formtapered concaves; a third step of patterning the silicon nitride layerin its portion located on the surface side of the silicon substrateremote from the tapered concaves to form a pattern having small openingssuch that the center of each opening substantially conforms to thecenter of each tapered concave through the silicon substrate; a fourthstep of forming a mask thin film on both surfaces of the siliconsubstrate and patterning the mask thin film in its portion located onthe surface side of the silicon substrate remote from tapered concavesto form a mask pattern having fine openings located within the smallopenings; a fifth step of forming through fine holes in the siliconsubstrate by deep etching using, as a mask, the mask pattern and themask thin film; a sixth step of removing the mask pattern and the maskthin film and oxidizing sites within the through fine holes in thesilicone substrate, sites exposed within the small openings, and sitesexposed within the tapered concaves to form a silicon oxide layer; and aseventh step of removing the silicon nitride layer and removing a partof the silicon substrate by dry etching using the silicon oxide layer asa mask from the surface side of the silicon substrate remote from thetapered concaves to form nozzle bases having a predetermined length,thereby forming fine nozzles.
 14. A process for producing a plurality offine nozzles, formed of silicon oxide, protruded from one surface of asilicon substrate and in communication with fine holes which extendthrough the silicon substrate and have a silicon oxide layer on the wallsurface thereof, said process comprising: a first step of providing asilicon substrate having on its whole surface a silicon nitride layer,forming a mask pattern having a plurality of fine openings on thesilicon nitride layer in its portion located on one surface of thesilicon substrate, and forming, on the silicon nitride layer on theother surface of the silicon substrate, a mask pattern having wideopenings such that the center of each wide opening substantiallyconforms to the center of each fine opening through the siliconsubstrate; a second step of forming fine holes having predetermineddepth in the silicon substrate by deep etching using the mask patternhaving fine openings as a mask; a third step of forming wide concaves inthe silicon substrate by deep etching using the mask pattern having wideopenings as a mask in such a manner that the openings of the fine holesare exposed within the wide concaves, thereby forming multistagedconcaves; a fourth step of removing the mask pattern and oxidizing siteswithin the fine holes of the silicon substrate and sites exposed withinthe wide concaves to form a silicon oxide layer; and a fifth step ofremoving a part of the silicon nitride layer and a part of the siliconsubstrate from the surface of the silicon substrate remote from the wideconcaves by dry etching to expose the silicon oxide layer by apredetermined length, thereby forming fine nozzles.
 15. A process forproducing a plurality of fine nozzles protruded from one surface of asilicon substrate, said fine nozzles comprising a nozzle base, providedintegrally with the silicon substrate, and a silicon oxide end facelayer covering the front end face of the nozzle base, said nozzle basebeing in communication with fine holes, which extend through the siliconsubstrate and have a silicon oxide layer on the wall surface thereof,and having a silicon oxide inner surface layer on its inner wallsurface, said process comprising: a first step of providing a siliconsubstrate having on its whole surface a silicon nitride layer andpatterning the silicon nitride layer in its portion located on onesurface of the silicon substrate to form a pattern having a plurality ofsmall openings; a second step of forming a mask thin film so as to coverthe pattern of the silicon nitride layer and then patterning the maskthin film to form a mask pattern having fine openings located within thesmall openings, and, in addition, patterning the mask thin film on theother surface to form a mask pattern having wide openings such that thecenter of each wide opening substantially conforms to the center of eachfine opening through the silicon substrate; a third step of forming fineholes having predetermined depth in the silicon substrate by deepetching using the mask pattern having fine openings as a mask; a fourthstep of forming wide concaves in the silicon substrate by deep etchingusing the mask pattern having wide openings as a mask in such a mannerthat the openings of the fine holes are exposed within the wideconcaves, thereby forming multistaged concaves; a fifth step of removingthe mask pattern and oxidizing sites within the fine holes of thesilicon substrate, sites exposed within the wide concaves, and sitesexposed within the small openings to form a silicon oxide layer; and asixth step of removing the silicon nitride layer and removing a part ofthe silicon substrate by dry etching using the silicon oxide layer as amask from the surface of the silicon substrate remote from the wideconcaves to form nozzle bases having a predetermined length, therebyforming fine nozzles.
 16. An apparatus for fine pattern formationcomprising: a silicon substrate; a plurality of fine holes which extendthrough the silicon substrate from the surface of the silicon substrateto the back surface of the silicon substrate and have a silicon oxidelayer on the wall surface thereof; fine nozzles which are protruded,integrally with the silicon oxide layer, on the back surface side of thesilicon substrate from each opening of the fine holes; a reinforcinglayer provided at least on the front end face and outer face of the finenozzles; a support member provided on the surface side of the siliconsubstrate; an ink passage for supplying ink to the opening of each finehole on the surface side of the silicon substrate; and an ink supplyingdevice connected to the ink passage.
 17. The apparatus for fine patternformation according to claim 16, wherein the thickness of thereinforcing layer is at least twice the thickness of the fine nozzles.18. The apparatus for fine pattern formation according to claim 17,wherein the reinforcing layer is formed of any one of silicon oxide andphosphorus silicon glass.
 19. The apparatus for fine pattern formationaccording to any one of claims 16 to 18, wherein the fine nozzles havean opening diameter in the range of 1 to 100 μm and are provided at apitch in the range of 4 to 1000 μm.
 20. The apparatus for fine patternformation according to any one of claims 16 to 19, wherein the finenozzles have a projection length in the range of 10 to 400 μm.
 21. Theapparatus for fine pattern formation according to any one of claims 16to 20, wherein the fine holes in their openings on the surface side ofthe silicon substrate are in the form of tapered concaves which havebeen widened toward the surface side of the silicon substrate.
 22. Theapparatus for fine pattern formation according to any one of claims 16to 20, wherein the fine holes in their openings on the surface side ofthe silicon substrate are in the form of multistaged concaves which havebeen widened toward the surface side of the silicon substrate.
 23. Theapparatus for fine pattern formation according to any one of claims 16to 22, wherein the fine holes are divided into two or more groups andink passages are provided separately from each other or one another forrespective fine hole groups.
 24. The apparatus for fine pattern formation according to any one of claims 16 to 23, wherein a water-repellentlayer is provided at least on the reinforcing layer, provided on theouter face of the fine nozzles, and on the back surface side of thesilicon substrate.
 25. The apparatus for fine pattern formationaccording to claim 24, wherein the water-repellent layer is formed offluorocarbon.
 26. An apparatus for fine pattern formation, comprising: asilicon substrate; a plurality of fine holes provided so as to extendthrough the silicon substrate from the surface of the silicon substrateto the back surface of the silicon substrate; a main electrode providedon the surface side of the silicon substrate; a counter electrodeprovided on the back surface side of the silicon substrate while leavinga predetermined space between the main electrode and the counterelectrode; a support member provided on the surface side of the siliconsubstrate; an ink passage for supplying ink to openings in the fineholes on the surface side of the silicon substrate; and an ink supplyingdevice connected to the ink passage.
 27. The apparatus for fine patternformation according to claim 26, wherein nozzles are protruded on theback surface side of the silicon substrate from the openings of the fineholes.
 28. The apparatus for fine pattern formation according to claim27, wherein the wall surface of the fine holes has a silicon oxide layerand the nozzles are formed of silicon oxide.
 29. The apparatus for finepattern formation according to any one of claims 26 to 28, wherein thecounter electrode is in a drum or flat plate form.
 30. The apparatus forfine pattern formation according to any one of claims 26 to 29, whereinthe fine holes have an opening diameter in the range of 1 to 100 μm andare provided at a pitch in the range of 2 to 1000 μm.
 31. The apparatusfor fine pattern formation according to any one of claims 27 to 30,wherein the nozzles have a protrusion length in the range of 10 to 400μm.
 32. The apparatus for fine pattern formation according to any one ofclaims 26 to 31, wherein the fine holes in their openings on the surfaceside of the silicon substrate are in the form of tapered concaves whichhave been widened toward the surface side of the silicon substrate. 33.The apparatus for fine pattern formation according to any one of claims26 to 31, wherein the fine holes in their openings on the surface sideof the silicon substrate are in the form of multistaged concaves whichhave been widened toward the surface side of the silicon substrate. 34.The apparatus for fine pattern formation according to any one of claims26 to 33, wherein fine holes are divided into two or more groups and inkpassages are provided separately from each other or one another forrespective fine hole groups.
 35. The apparatus for fine patternformation according to claim 34, wherein main electrodes are separatelyprovided for respective fine hole groups.
 36. A method for fine patternformation, comprising the step of: while relatively scanning theapparatus for fine pattern formation according to any one of claims 26to 35 and a pattern object in a predetermined direction, continuously orintermittently ejecting ink supplied at low pressure from the inkpassage onto the pattern object through the fine holes in such a statethat a voltage is applied to the main electrode in the apparatus forfine pattern formation, whereby a stripe pattern or a dot pattern isformed.
 37. The method for fine pattern formation according to claim 36,wherein stripes constituting the pattern are formed by supplying inkthrough a plurality of fine holes arranged on an identical line alongthe scanning direction.
 38. A method for fine pattern formation,comprising the steps of: disposing the apparatus for fine patternformation according to any one of claims 26 to 35 at a predeterminedposition of a pattern object; and ejecting a given amount of inksupplied at low pressure from the ink passage onto the pattern objectthrough the fine holes in such a state that a voltage is applied to themain electrode of the apparatus for fine pattern formation, whereby apattern is formed.
 39. A method for fine pattern formation according toany one of claims 36 to 38, wherein the voltage applied to the mainelectrode is regulated to control ink ejection width and the amount ofink ejected.